You should probably be more specific as to what you're looking for. Do you mean any films at all? Do you mean American films? Do you mean mainstream Hollywood films?

For instance, [Oscar Micheaux] (https://en.wikipedia.org/wiki/Oscar_Micheaux) was one of the first prominent black filmmakers in America, and all of his films feature black casts -- the first in 1918 -- however he was an independent filmmaker working entirely outside of the Hollywood studio system, and his movies mostly played to black audiences outside of mainstream theaters.

[Stepin Fetchit] (https://en.wikipedia.org/wiki/Stepin_Fetchit) was more prominent to mainstream audiences in the 1930s, however he was also an embarrassment to most African-Americans, as his comedic persona fulfilled many of the worst stereotypes about black people (lazy, stupid, etc.). Even today, his name is used as a shorthand for degrading black stereotypes. Several other actors followed in his footsteps during this era.

[Sidney Poitier] (https://en.wikipedia.org/wiki/Sidney_Poitier) is often regarded as one of the earliest black actors to be a genuine leading-man movie star in mainstream Hollywood, with his first leading roles in the late-'50s, and was equally the first to win an Best Actor Oscar (in 1963). Unlike Fetchit and many similar actors, Poitier's roles were respectable and dramatic ones that could put him in equal company with a Paul Newman or Clint Eastwood, an actor that could be admired and idolized.

Paul Robeson was a mainstream american actor prior to Poitier, although he was black listed and so is not well known today. Also look up Dorothy Dandridge who was the first african american to be nominated for the Oscar for best actress for Carmen in 1954. She made few more movies in the late 50s, then died under some odd circumstances when she was 42.