So, now that Marvel Studios has regained the rights to all of the characters from Fox's stable of Marvel characters I had a couple of ideas on how they can begin to integrate them into their universe and build up to an eventual X-Men film (perhaps Uncanny X-Men or Astonishing X-Men). I think Mutants could have been in hiding and Xavier's School haven't intervened because they are scared of persecution, maybe something kept quiet in the past by the US Government.
1) First up, quite an easy one to work in I believe. Ororo Munroe aka Storm. I think it would be quite easy to integrate the African Goddess-like mutant into the upcoming sequel Black Panther II. Perhaps even introducing her as an ally and love interest to T'Challa. I could see Aja Naomi King (How to Get Away with Murder), Gabrielle Union (L.A.'s Finest) or Jessica Lucas (Gotham) pulling off a convincing Storm.
2) As for that persecution I mentioned earlier who better to be behind it than Senator Robert Kelly? Kelly blames mutants for the death of his wife, Sharon, a former Hellfire Club waitress. He could have ties to General Ross especially as they share views on superpowered individuals being controlled/registered. Perhaps Kelly had some success in the past with the Mutant Registration Act and Ross, after being betrayed by Black Widow, goes to Kelly for advice. For Senator Kelly I could see Christopher McDonald (Ballers).
3) Ross' views on the Avengers might have changed after Endgame but it's a pretty safe bet to say that they haven't; so, with Kelly's help perhaps they could assign Henry Peter Gyrich as the Avenger's liaison, keeping tabs on the superpowered individuals that are still in the fold and making their life all that bit more difficult. He has a history of clashing with mutants also and was a key part in Operation: Zero Tolerance with Bastion which lead to mutants being hunted down. I would suggest Rory Kinnear (Years and Years) for the role.
More to come...