Answer: Concern over the fur trade.
The French and Indian War is the name given to the part of the Seven Years' War that was fought in North America. It is named that way because of the two enemies of the British colonists: French colonists and Native Americans.
During this war, Native Americans were mostly on the side of the French. This was due to several reasons. The most important one is the fact that the French dominated the fur trade from the St. Lawrence River (present Quebec) to the Mississippi. The fur trade was an important source of revenue of Native communities. Another important reason is the fact that interactions with the French population were mostly amicable. The lifestyle of the Native Americans was respected, and intermarriages were common. French officials often adopted Indian habits and all the Native population was considered citizens of France.