What is the term used to describe seventies films that featured african american actors in heroic roles?

The answer is " Blaxploitation".

Blaxploitation is a term used in the mid 1970s to allude to dark activity films that were gone for dark groups of onlookers. Including African-American performers in lead parts and regularly having insurrectionary plots, the movies were much of the time denounced for cliché portrayal and glorification of viciousness.