Usman is going to the UFC in a few years, either after he finishes his renewed contract or if PFL goes down. Khabib has said that the plan is for Islam to retire and have Usman take his place. Hughes, Usman, Gadzhi and AJ are all high level guys so I hope we get to see them all in the UFC down the line, preferably before they're washed.
Hope Vadim doesn't re-sign with PFL tbh, a fight with Ngannou would be cool but after that? Goltsov, Delija, Popov and Moldavsky are all mid (and the latter two are his teammates), Renan has a puncher's chance and that's it.