They are Cheyenne
Buddy and Philbert have two different views of what Cheyenne is. Their views could also be seen as coming from different sources, one from the outside world looking at the Cheyenne and one from the Cheyenne looking at themselves and their past. Buddy seems to look at the Cheyenne as "outsiders" do. He knows that people see them as poor and stupid and tries to change that but at the same time he seems to view their traditions as holding them back and keeping them stupid in a way. He want Philbert to make his car look nicer and gets angry at the salesman because he knows that people look at them as stupid just because they are Native Americans. Philbert on the other hand views Cheyenne as descendants of their ancestors and people who should be keeping their traditions alive. He replies to Buddy's request for a ride that "we are Cheyenne" as if there is no question of whether or not he will help because they are Cheyenne so he must. It seems that he has asked his aunt about Cheyenne tradition many times because she seems to angry and tired of his questions when he asks her about gathering medicine. And his whole journey is based on gathering medicine to become a warrior and based off signs and visions. Their two views of the Cheyenne seem to get reconciled a bit throughout the movie as Buddy accepts Philbert's view of the Cheyenne and seems to worry less about how others see him as well as the fact that Philbert seems to have gained a bit more understanding of how others see the Cheyenne by the end of the film.