There has been a lot of speculation about how (and even if) Ant-Man and the Wasp will affect the wider Marvel Cinematic Universe moving forward, considering it will further explore the Quantum Realm as our heroes venture inward to save Janet van Dyne, played by Michelle Pfeiffer, who has been trapped there for decades. As Slash Film was speaking to the director, Peyton Reed, during the set visit, someone asked what the primary mission of this movie was for these characters and got a rather ominous answer.
Well, I’ll answer that in two parts,” he said. “The big mission is to find Janet. What that means ultimately for our characters on a personal level is one thing, and what it means for the larger world is another thing, and all the other things are really stumbling blocks on the path.
What seems to be implied here is that their mission in saving Janet will have a great personal effect on Hank, Hope, and Scott in this movie, but that it could definitely have larger ramifications for the wider MCU moving forward.
It’s likely that Scott and Hope discover something about the Quantum Realm as they’re saving Janet that could be used in Avengers 4 to stop Thanos and help save everyone who was snapped away at the end of Avengers: Infinity War or Janet herself discovered something while trapped in the Quantum Realm and relays her discovery to Hank, Hope, and Scott when they save her.
Source: Slash Film