Native American activist Amanda Blackhorse -- a social justice leader who helped force Washington's NFL team to change its name -- is now calling for the Chiefs to switch their moniker ... and she's urging Rihanna and Patrick Mahomes to join the cause this week.
Blackhorse and other Indigenous advocates have scheduled a protest at State Farm Stadium on Sunday during the Super Bowl ... in an effort to get the ball rolling on ridding K.C. of its longstanding team name.