A piece of trivia that has been rattling around in my brain for decades, source unknown: Poitier made 21 movies over fifteen years before being cast in a film in which the race of his character was not a plot point: The Bedford Incident, 1965.
Now, I haven’t watched all 20 of those earlier films (or TBI, for that matter), so I can’t personally verify this factoid, but it seems plausible.