I assume you mean Sub-Saharan African peoples and not North Africans like Libyans and Amazigh peoples (Berbers) who inhabited regions of Roman provincial Africa and of course the Egyptian people. Fortunately I can say that there was much more Roman interaction with Sub-Saharan Africa than you might imagine!

Now it would be a terrible oversight for me to imply that the peoples of Sub-Saharan Africa were all "tribes" because there were kingdoms, cities, dynasties and other social structures dating back millenia even in Antiquity. Technically we can define family lines, clans, peoples or even dynasties as "tribes" in the way that we might translate the Roman term gens which can also mean a people or a family as "tribe", but since the term "tribe" tends to evoke a sense of primitivism or savagery that makes it's use in this way more misleading than not as /u/commustar noted.

Sub-Saharan Africans were referred to as Aethiopians by Greeks and Romans but this catch-all name for peoples living south of Egypt and although it refers especially to dark-skinned Africans it was also used for light-skinned peoples living in Africa. The utility of the term to modern historians and anthropologists is minimal since it includes numerous cultures and ethnic groups, and even ancient authors distinguished between different "Aethiopian" peoples.

Most Greco-Roman authors do consider most Aethiopians to share some physical and cultural traits in common, as per usual for ancient proto-ethnographic observations. These physical traits included dark skin, wooly, coiled or curled hair, flat features and tall, slender bodies. Cultural stereotypes of Ethiopians included their extreme piety, ferocity, health, and semi-nomadic (and therefore by Greco-Roman standards barbaric) life style.

While use of the term "Aethiopian" is as useless as referring to Greeks, Celts, Italic peoples, Thracians and other ancient peoples under a blanket "European" term, it actually mirrors all the flaws in the concept of "Sub-Saharan Africa" as both a monolithic whole and distinct body from North Africa so it would be a mistake to point out the errors in the former while ignoring the latter's issues.

With this in mind, I think we are ready to explore the role of Roman activity in Sub-Saharan Africa and Sub-Saharan African activity in the Roman Empire.

#[1/3] Saharan/Sudanic Africa and Sub-Saharan/East Africa

The Saharan African kingdom which interacted with Rome most closely was Meröitic Nubia. The area referred to as Nubia or Kush by modern historians, and Aethiopia by Greco-Roman authors, had an ancient history stretching back thousands of years even at the time that Greeks and Romans set about describing it. Multiple distinct "kingdoms" are defined by historians but the "Meröitic" kingdom is so named because it had its capital in the ancient city of Meröe (about 200 km to the north of Khartoum, the modern day capital of Sudan) as opposed to the previous Nubian capital in Napata. The kingdom of Nubia at its greatest extent, not counting the Nubian rule of Egypt by the 25th dynasty, stretched from the First Cataract of the Nile (near modern day Aswan, Egypt) in the north to Khartoum in the south and from the Libyan desert (part of the northeast Sahara) in the West to the Red Sea coast in the east. This kingdom controlled vital trade routes further into the African interior through which ivory, exotic animals (including rhinoceroses and elephants), slaves and luxury items were obtained. Within Nubia, mines and quarries produced gold, iron and precious marbles and stones, some of which were exported to the Roman Empire through the province of Egypt. Sea ports on the Red Sea allowed for maritime trade with Arabia and India which included timbers, gems, silks, spices and other commodities.

I talked about the war, reconciliation, and trade relationship between Meröe and Rome that occurred in the reigns of Queen Amanerinas the one-eyed and Augustus here.

A strong connection between Meröitic Nubia and the Mediterranean through trade is attested to not just through literary and textual accounts of trade relationships, but through material evidence as well. Hellenistic and Roman influences on Nubian architecture can be seen at sites like "Royal Baths" in Meröe, as well as the remains of small idols and votive objects in Greco-Roman design. Extremely refined and glossy black fineware which is found in Meröe has been suggested to imitate Hellenistic silverware which was known for being glossy and black, and imported pottery is also evidenced in Lower Nubia.

Meröe does not seem to have used the "polis" model of state building around an urban nucleus which is in and of itself unsurprising since Napatan, Egyptian, Persian, and Celtic peoples did not either. However, unlike many of these civilisations, we do not know exactly how Meröitic urban centres were organised. A walled enclosure, referred to as the "Royal City", has been excavated which contained several palatial structures, lay at the heart of an urban complex in Meröe. Outside of the enclosure lay several large temples and temple complexes, settlement mounds and workshops. Whether Meröe was merely a political and religious hub with a supporting population of workers or a truly urban settlement is as yet unknown but other settlements in Meröitic Nubia are known to have been urban settlements. For instance the settlement of Hamadab, near to the south of Meröe, was spread between two hills on opposite sides of the Nile River and included both temples, monuments and residential structures. Napata, the previous capital of Nubia continued to have some importance even after it was superceded by Meröe.

Edwards in The Nubian Past calls Meröe "the greatest state hitherto seen in Sub-Saharan Africa" because of its imperialistic outlook, vibrant culture and impressive state building. Obviously something like "the greatest state" is debatable (like crips and bloods Romans or Greeks) but Meröe was certainly one of the most influential Sub-Saharan cultures in Classical Antiquity.

There is evidence of numerous modes of subsistence in the Meröitic kingdom including sedentary agricultural subsistence (based on crops like sorghum, barley and wheat), semi-sedentary reliance on crops and livestock, reliance on livestock and pastoralism rather than a grain or vegetable based diet, and reliance on imported foodstuffs by the disproportionately literate and elite inhabitants of outposts and settlements in Lower Nubia.

Semi-nomadic pastoralists are known to have ranged from what is modern day central Sudan to the Mareb river in Eritrea, and were related to pastoralists in the Ethiopian highlands.

If you were looking specifically for information on Sub Saharan nomadic peoples, then there were kingdoms and clans of nomadic or semi-nomadic peoples who hunted and traded with Nubia and Egypt, or inhabited the margins of these empires.

The Troglodytes were reputedly cave dwellers who inhabited parts of modern day Eritrea and Ethiopia. They are said to have subsisted on hunting and trading with the Kushites and Egyptians. Their language was described as being shrill, high pitched and harsh on the ears by Greco-Roman authors, and the "Troglodytic" tongue is listed by the Roman historian Plutarch as being one of the languages that Cleopatra spoke. That particular anecdote very likely has to do with the significance of the Troglodytes to Ptolemaic Egypt's Red Sea trade.

The Blemmyes were a semi-nomadic kingdom within the Meröitic Sudan who had strong ties to Nubian and Egyptian cultures, and indirect ties to the Mediterranean through these. In earlier times they had been largely unknown to the Mediterranean and some Greek authors even claimed that they were headless but had their faces in their chests. However by the Hellenistic period Mediterranean authors had become more familiar with Africa and after the Roman conquest of Egypt the Blemmyes became more distinguished. As the Blemmye kingdom began to rise by the late 3rd Century CE, the Roman Empire had to deal with frequent raids on their Egyptian frontier, although there were a few times that the Romans allied with the Blemmyae.

The Roman Diodorus Siculus describes numerous peoples who inhabited "Aethiopia" in the beginning part of the third book of his Library of Histories. He distinguishes between the people dwelling in the capital and island of Meröe, and in Lower Nubia from those who dwell in the rest of the country by the differences in their customs. He describes some who subsist on fruits and vegetables, some who subsist on dairy from their herds of sheep and cattle, and some who subsist on hunting. Diodorus' account is flawed to be sure, but many of his observations about the geography of the country and Nubian religious iconography indicate a knowledge of the country.

Bows, spears and clubs are attested to as archetypal weapons of these regions. Nubians in particular were noted for their skill at archery while other peoples in the region were also apparently proficient in bow and spear. Iron tools and weapons were used in Meröe but stone tipped arrows and spears were also used in ancient East and Northeast Africa, including Egypt. Nubian warriors are depicted in Egyptian art and described by Roman authors as dressing in leopard skins, and it is worth noting that the geographic range of these animals was much higher in Antiquity. Chariot archers and axe-wielding African armies are also mentioned by Greco-Roman authors as serving as auxiliaries in armies like that of the Persians, Egyptians and Carthaginians.

[Continued Below]

I don't know what a tribe is, so I can't really speak to that. Edit- Scholars of African history don't use the word 'tribe' anymore because of the word's problematic application in the colonial era, and its lack of a clear definition.

However, there have been several questions about Roman contact with African peoples that might interest you.

I wrote this answer a few years ago, as well as this answer about roman-nubian interaction

/u/Khosikulu wrote about roman exploration in this thread

and /u/Cleopatra_philopater wrote about Ptolemaic and Roman interaction with Meroe here