There's quite a variety of ways that the Five Tribes and the State of Oklahoma / the federal government can resolve this, two of the extremes being "Congress formalizes its reneging on its treaties with the Five Tribes, thus fucking over Native Americans yet again, but in writing this time" and "Tulsa experiences karmic retribution in the form of Trail of Tears 2: Electric Boogaloo".

Hopefully neither happens, and instead we get something that at least tries to work to the interests of both parties, e.g. "non-tribal residents are allowed to stay but are subject to tribal law (and pay "state" taxes to applicable tribal authorities instead of Oklahoma)" or "Oklahoma and/or Congress pays the Five Tribes a fair price for lands already occupied by population centers (e.g. Tulsa) and releases the rest to respective tribal authorities" or somesuch. Or perhaps something even crazier, like "the Five Tribes make another attempt at founding the State of Sequoyah" (with Tulsa being a decent-enough candidate for becoming a state capital).

Realistically, though, knowing this country's tendencies toward addressing hard-to-solve issues, the most likely outcome is "nothing changes and Schrödinger's Indian Reservations continue to simultaneously exist and not exist".