While not an overwhelming success in comparison with other superhero movies, Peyton Reed's Ant-Man successfully introduced the idea of a multiverse via the Quantum Realm. Before Doctor Strange expanded on the concept of different dimensions, Ant-Man hinted that the shared universe can expand in other directions than just outer space.
The Ant-Man sequel, Ant-Man and the Wasp, has wrapped up shooting and is scheduled for a July 2018 release. Thanks to Evangeline Lilly, we already know that this sequel will have a great impact on the future of the Marvel Cinematic Universe.
During an interview with Vanity Fair, the actress explained what Disney CEU Bob Iger meant when he stated that the MCU would expand into different realms, including space and time. She added that she didn't know what would happen after Ant-Man and the Wasp (since she doesn't create the stories), but the sequel will open the multiverse:
When I heard about Infinity War, and the direction that they're heading, I did have this moment of realizing, oh, wow, there's a bit of a déjà vu for me with the Lost franchise. We are hitting that [Lost] Season 4 space where everything's about to shift, and you're about to lose the solid ground underneath you. And [Ant-Man and the Wasp], of course, will play a part in that. Those characters are experts in the Quantum Realm. In Ant-Man and the Wasp, they are trying everything in their power to safely enter the Quantum Realm and return from it, because they have evidence from the first film that Scott Lang was able to do that. If he can do it, why can't we? If we do succeed in Ant-Man and the Wasp, then that does open a whole new multi-verse to enter into and play around in. I'm not the story creator, so I can't tell you what they're going to do with that. But I definitely see the potential there.
Ant-Man and the Wasp will be released on July 6, 2018. We still don't know anything in particular about the film’s plot, but it has to be big, especially since it’s the first movie to follow Avengers: Infinity War.