Ant-Man is the final movie from Marvel's Phase II and there are high expectations as far as it is concerned - but all is good, since voices from the studio can be heard, according to whom this might be the best Marvel (solo) movie yet.
However, how will it connect to the rest of the MCU? This is a question which needs to be asked, especially since the original Ant-Man Hank Pym was actually the creator of Ultron. Furthermore, Hank Pym is also one of the founding members of the Avengers, together with his wife Janet Van Dyne (The Wasp).
Well, there is a scoop about the role of the diminutive superhero in the Avengers, as well as some other connection to the larger MCU.
Ant-Man - the Cold War
As it is already known, there will be a couple of scenes taking place during the Cold War. It is now when the younger Hank Pym will meet with Howard Stark and Peggy Carter, presumably in the "˜60's. But this isn't all - another connection will be made when the same young Ant-Man will meet with Thaddeus "Thunderbolt" Ross. This is the father of Betty Ross - both of them appeared in 2008, in The Incredible Hulk.
It is safe to assume that the basis of the Avengers initiative will also be placed now. Furthermore, given the scientific genius of Hank Pym and his hate for all superheroes (as it will be stated in the movie), this young character might also come up with the Ultron program (the one Tony Stark will try to resurrect during Avengers: Age of Ultron).
Ant-Man - Civil War
The same scoop also says that Hank Pym will ally with General Ross and Tony Stark after Avengers: Age of Ultron - they will all plead in the favor of the Registration Act, which will eventually lead to a clash with Captain America and his own team.
During the Civil War, Black Widow will be imprisoned - the new Ant-Man Scott Lang will again put on the suit, but this time not for a heist but a daring prison escape.
But then again, these all should be taken with a pinch of salt, even if they do make sense as far as the MCU is concerned.