Having just come back from a trip to Tuba City in Northern Arizona, I can say that there is little love lost between today’s Navajo and the Hopi. Take away the minimum comfort level today’s society provides, and there would certainly be blood.
Navajo and Apache (Athabascan tribes) stole land from Hopi and Zuni (Pueblo tribes), who - if I remember correctly, predated the arrival of the Athabascan tribes by about 1,000 years.