When Marlon Brando won the best actor Oscar for Francis Ford Coppola's classic film The Godfather, he refused the award and sent a Native American Indigenous woman by the name Sacheen Littlefeather to refuse it on his behalf. He had typed an 8 page letter, but the organizers only gave her 60 seconds to speak.
She advocated for the lack of representation of Native American people in film and television. She was the first woman of color and indigenous woman to ever make a political statement at the Oscars.
You can watch a trailer for a short film made about her:
https://www.onebowlproductions.com/sacheen