In George Romero's Night of the Living Dead, he cast a black lead actor as Ben in 1968, during the height of the civil rights movement. The ending was a commentary on the state of racism and police brutality toward black Americans, where Ben is killed despite being uninfected.
In 1978's Dawn of the Dead, Peter is a leading black man and is one of only two to make it to the end of the film. The opening of the film is a swat team raiding project housing and brutally murdering both infected and uninfected.
In 1985's Day of the Dead, John is the group's helicopter pilot and source of wisdom and calm. He's the only character who can get them out, and again one of the only people to make to the end of the film.