By now, we all know that Marvel Studios has a plan set in place for their Phase 4 films and that they are currently deep in the planning and development stages for them. We just don't know what all of those movies are! There's been a lot of talk and speculation about what those film could be the only two we know are coming for sure are Spider-Man: Far From Home and Guardians of the Galaxy Vol. 3.
Now a new report has surfaced from GWW that indicates that Marvel Studios is looking to shoot a yet to be announced film in the UK in June of 2019. That outlet lists three possibilities... The Eternals, Black Widow, and Doctor Strange 2.
Doctor Strange 2 might be the likely candidate as a separate report from The Mirror is saying that Benedict Cumberbatch is getting a major pay raise to return to the role and they indicate that the film shooting next year.
It could also be Black Widow, due to the fact that the film already has a director attached. That director is Cate Shortland and Scarlett Johansson is set to reprise her role.
As for The Eternals, that's the least likely project as the project just recently entered the writing phase with screenwriters Matthew and Ryan Firpo.
With all these films in various stages of development, none of them have been officially greenlit or announced by the studio yet. I imagine that there's probably going to be two or three Marvel films go into production throughout next year. It'll be interesting to see what those movies will be. Marvel has no plans on revealing their Phase 4 slate of films until after Avengers 4 is released as to avoid spoilers.
We most likely won't get an official announcement until Comic-Con next year, so we've got a long time to wait.