*The following contains spoilers for Captain America: Civil War
The astonishing Ant-Man/Giant-Man went all out in Captain America: Civil War. I am really excited in the direction Marvel and Paul Rudd are taking the character of Ant-Man, and I am curious on how the events of Infinity War will go in part with Ant-Man’s next installment: Ant-Man & the Wasp.
After The Civil War
At the end of Captain America: Civil War, Cap breaks into the underwater prison where Scarlet Witch, Hawkeye, Falcon, and Ant-Man are, breaking them out. From there we are left to speculate to the whereabouts of the new secret Avengers.
We know that the first Infinity War movie comes around May 2018, but soon after, we will also get to see Ant-Man & the Wasp in the summer of that same year.
Back To The Past?
One possibility is that the movie Ant-Man & the Wasp could be primarily centered on Hank Pym and his wife rather than Scott Lang and Hank’s daughter Hope. I don’t think Marvel will go in that direction though, since going back in time, backwards in the Marvel Cinematic Universe, would disrupt the overall direction the MCU is heading. In addition, we got a sneak peak of the new Wasp costume at the end-credit scene of Ant-Man, so it is more than likely that Evangeline Lilly's Hope van Dyne will be the one taking on the Wasp mantle in the sequel.
My theory is that Wasp will be introduced in the first Infinity War movie, and after the events of that movie, something will happen where both her and Ant-Man will be sent or be trapped in a different dimension. The Ant-man & the Wasp movie would then concentrate on them working towards returning to the fight with Thanos and on the way, encountering a new villain.
Quantum Realm & Different Dimensions
Ant-Man recently experienced the quantum realm in his own movie, but the quantum realm is not necessarily a different dimension but more of a deeper level within human reality. So the dimension they would be at would not be the quantum realm. Think of the quantum realm like looking through a microscope; you will see things that you couldn't see with the naked eye. Now, make that notion 10 times smaller, 100 times smaller, as small as you can think, that is the quantum realm.
The possibilities of different dimensions and different worlds is possible thanks to the upcoming Doctor Strange film. The concept of dimensions and other worlds will be as evenly exciting when the Guardians of the Galaxy finally meet the Avengers some time in the future, hopefully during the Infinity War movies.
Expanding The Theory
If Ant-Man and Wasp are sent on a mission through a trans-dimensional gateway by Doctor Strange, or end up lost in the cosmos with the Guardians of the Galaxy, that is another possible scenario that will lead to the Ant-Man & the Wasp movie. Because Ant-Man recently turned giant in Captain America: Civil War, he could then in some way, be of help to the Guardians in his giant form, or vice versa. We could then potentially see Star-Lord, Rocket Raccoon, Groot and Gamora make an appearance in Ant-Man & the Wasp. While not officially confirmed, Anthony Russo, the director of the Infinity War movies along with his brother Joe Russo, teased the appearance of Chris Pratt in the Infinity War movies when speaking with Comicbook.com last April:
"The movies are intended to be a culmination of everything that’s happened before in the MCU so you don’t want to get into spoilers but I’m a big fan of what James Gunn has done. [Joe Russo and I] are both big fans of what James Gunn has done. Star-Lord is a fantastic character and Chris Pratt is an awesome performer so you’d be very excited."
Ant-Man and the Wasp is part of the MCU's Phase Three set of movies and is scheduled to release on July 6, 2018. Before Ant-Man and the Wasp, the first Infinity War movie is scheduled to release on May 4, 2018.