An actors job is to portray someone else.
On TMC I was watching a movie called “The Good Earth” about Chinese farmers. 2 Caucasian actors played the Chinese characters. They were believable. That’s what acting is.
Who was the Italian guy that portrayed the Indian with a tear running down his cheek?
Yes, but they were able to adjust Paul Muni and Luise Rainer a bit to make it more believable. It’d be hard to adjust a black to a yellow, etc.