This post contains spoilers for Ant-Man and the Wasp and Avengers: Infinity War, as well as speculation for Avengers 4.
Ever since Avengers: Infinity War absolutely devastated us by turning half the Marvel Cinematic Universe to literal dust, people have been trying to figure out how exactly Marvel will bring everyone back in the next Avengers.
Most fans agree that time travel will play a key part in defeating Thanos/saving the lives of our faves.
In the mid-credits scene of Ant-Man and the Wasp, Scott enters the Quantum Realm with the help of Hope, Janet, and Hank.
As both Ant-Man movies constantly reiterate, time and space work very differently in the Quantum Realm. But even more significantly: Janet warns Scott before he enters to be careful of "time vortexes" down there.
Here's where it gets really interesting: That someone could very well be Captain Marvel.
All in all, it seems like Ant-Man, Captain Marvel, and time vortexes in the Quantum Realm will play key parts in defeating that purple bastard Thanos.