In 1973, Sacheen Littlefeather took the stage to reject an Oscar on behalf of Marlon Brando. She was given 60 seconds on stage to provide the following speech:

“Hello. My name is Sacheen Littlefeather. I'm Apache and I am president of the National Native American Affirmative Image Committee. I'm representing Marlon Brando this evening and he has asked me to tell you in a very long speech, which I cannot share with you presently because of time but I will be glad to share with the press afterwards, that he very regretfully cannot accept this very generous award. And the reasons for this being are the treatment of American Indians today by the film industry – excuse me – and on television in movie reruns, and also with recent happenings at Wounded Knee. I beg at this time that I have not intruded upon this evening and that we will in the future, our hearts and our understandings will meet with love and generosity. Thank you on behalf of Marlon Brando"

She kept her full composure despite the boos and jeers coming from the audience. John Wayne had to be restrained by security because he wanted to physically assault her as she left the stage. Clint Eastwood mocked her by saying that he was presenting the award on behalf of “all the cowboys shot in all the John Ford Westerns.” Subsequently, Littlefeather was blacklisted by Hollywood and never worked again.

Nearly half a century later, Littlefeather will return to the Academy as a guest of honor on September 17, 2022.

https://en.wikipedia.org/wiki/Sacheen_Littlefeather