H. R. 165 aims to ensure that certain land is held in restricted fee status by the Oglala Sioux Tribe and the Cheyenne River Sioux Tribe. This means the land will remain owned by the Tribes, be part of the Pine Ridge Indian Reservation, and won't be transferred or taxed...
Simple Explanation
H. R. 165 helps the Oglala Sioux Tribe and the Cheyenne River Sioux Tribe keep their land safe and free from being sold or taxed unless the tribes and Congress agree. Also, they can't build casinos on it.