They did. Cyborg. The character has always been black. He already showed up in a Justice League movie alongside white Superman.
They are already producing a backstory movie just about Cyborg.
Not sure how they're going to explain negro Superman suddenly showing up in the next Justice League move.
“They are already producing a backstory movie just about Cyborg.”
I don’t think that will happen. Ray Fisher, the guy that played him, seems to be persona non grata with Warner Bros. now. He has done a lot of public bellyaching about how some of the creators treated him. Racism, ya know. WB investigated his complaints and concluded they was no substance to his complaints.