Did you ever see Mankiewicz’s “No Way Out,” with Poitier as the black doctor and Widmark as the white gang leader who curses him as he gets treated? Very strong stuff for 1950. Inspired by the 1943 Detroit riots, btw.
I saw it a long time ago. But yeah that sort of thing wasn’t common at at that time at all. And of course there’s also 1947’s ‘Pinky’ about a light skinned black woman passing as white. But the less said about that the better.