Answer: They surrendered the right to millions of miles of ancestral lands.
Step-by-step explanation:
The Yakama like other American Indian tribes, came into conflict with the United States as Americans went westward towards the Pacific.
A treaty was agreed that would have seen them moved into a reservation but before Congress could ratify it, war broke out as the Yakama replaced their Chief with his brother who then agitated for war.
The U.S. won the war and moved the Yakama into reservations which led to them losing millions of miles of ancestral land.