[WARNING: This post contains SPOILERS for Ant-Man.]
Marvel Studios' Ant-Man has done well both commercially and critically (read our review), successfully expanding the Marvel Cinematic Universe in the process. One of the film's better received elements is Michael Douglas' performance as Hank Pym. Many feel the actor lent a certain amount of gravitas to Ant-Man and his character arc was rewarding, when it was all said and done.
Ant-Man occasionally flashes back to events from Pym's past, providing a brief look at his time as Ant-Man (and his complicated relationship with S.H.I.E.L.D.). Some fans have been hoping that Pym is someone who will be explored further in future projects, though right now Douglas isn't signed on for additional Marvel films.
Speaking with Yahoo! Movie UK, Douglas revealed that he did not sign the typical Marvel movie contract, which usually stipulates numerous films over a handful of years. However, he would like to reprise as Hank Pym (in an expanded capacity), should he get the chance:
“I’m not signed up to anything more. I’ve learned a whole lot and would look forward to more if it comes my way but if not I’ve enjoyed the experience. Now that I understand a bit more about Hank Pym too. I think in this one I had to carry a lot of plot and exposition. In the next one I hope things get a little more bizarre… the Quantum Realm!”
Ant-Man does concluded with a potential story thread left hanging, as Pym is renewed with hope that his wife Janet can be saved from the Quantum Realm (following Scott Lang's return during the climactic battle). Many viewers would no doubt be interested in seeing Pym doing some research on the Realm, as it potentially has a large role to play in Phase 3 of the MCU. Beyond that, this would provide a (hopefully) satisfying end for Hank's personal story.
Ant-Man star Paul Rudd will return in Captain America: Civil War and Evangeline Lilly's Hope van Dyme is set to become the Wasp, but the future involvement of other Ant-Man characters remains up in the air. It may be difficult to find room for Lang's heist buddies in any upcoming Phase 3 movies, but if Douglas returns then he will likely be a supporting player in someone else's solo movie (a la Spider-Man) or part of a larger ensemble (Avengers: Infinity War).
That doesn't mean Ant-Man 2 won't happen down the line, but seeing as the first movie didn't pack as much box office punch as other Marvel Studios films, it's more of a long shot. Marvel will continue on with lucrative properties like The Avengers and Guardians of the Galaxy, but an Ant-Man sequel will be a secondary concern at most. Scott Lang's individual adventures may continue in Phase 4, but best to not hold your breath (as Hulk fans can tell you).
Ant-Man is now playing in theaters; Captain America: Civil War arrives on May 6, 2016; Doctor Strange– November 4, 2016; Guardians of the Galaxy Vol. 2 – May 5, 2017; Spider-Man reboot – July 28, 2017; Thor: Ragnarok – November 3, 2017; The Avengers: Infinity War Part 1 – May 4, 2018; Black Panther– July 6, 2018; Captain Marvel – November 2, 2018; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019.
Source: Yahoo! Movies UK