It means Congress is shortly going to renege on yet another treaty they made with a Native American tribe.

Likely very little. There's about 20,000 people who report Native American as their ethnicity in Tulsa, and likely the number of tribal members is lower.

Nothing drastic. The real consequence is going to be to the state criminal justice system, where and who it applies to. Federal laws will still apply.

Here's most of it:

"Tribe members who live within the boundaries are now set to become exempt from certain state obligations such as paying state taxes, while certain Native Americans found guilty in state courts may be able to challenge their convictions on jurisdictional grounds. The tribe also may obtain more power to regulate alcohol sales and expand casino gambling. "