How late is late? By mid-15th century, with the emergence of munitions-grade armour such as the black sallet, which was designed to be made with as little work as possible and often remained unplanished and unpolished, more and more common soldiers could afford armour. This was also amplified by the fact that metal doesn't really deteriorate that much, so older equipment, even if outdated, could still be used, which is why many historians believe that at Battle of Visby (admittedly some 40 years before the start of 15th century) equipment that was severely outdated was used by the revolting peasants.

Unfortunately it is a difficult answer to give, and I hope someone can expand this, but period art often shows a more idealised image of a battlefield, so it should be taken with a grain of salt. However, multiple paintings by completely different artists appear to show fairly similar equipment used by the normal soldier during this time period. This would be a brigandine worn over a gambeson. Mail armour appears in some art, but not necessarily in all of it.

Examples of common soldiers depicted in art: here, here, or here. You can see just how ubiquitous the brigandine appeared to be in the mid-to-late 15th century, alongside the sallet helmet.

Most professional soldiers in mid-15th century, to answer, would probably wear a gambeson, a helmet, and a brigandine at the least, but full plate armour was certainly not unseen among men-at-arms. You will have to specify the time period pretty exactly though if you would like a more specific answer, as mid-14th to late-15th centuries saw massive sweeping changes in the design of plate armour.