Ant-Man Returns
After the big reveal of the title, the Avengers: Endgame trailer closes on a lighter note that helps add a bit of comic relief after the heavy-going past two minutes. But it also drops a pretty big revelation of its own: Ant-Man comes back!
In what could follow on from the scene featured earlier in the trailer, when Black Widow explains about the Decimation, Steve and Nat watch with slack jaws as Scott Lang appears at the front door of the Avengers facility. While he babbles away over the high-tech intercom, fearing that they’ve forgotten who he is, the pair wonder how it’s possible that he could still be alive.
As previously stated, he’s alive because he’s been trapped in the Quantum Ream – but what we want to know is how he got out of there. All the theories about Scott’s return tied into those ideas that Avengers: Endgame would open many years after the events of IW, which have clearly been proven false. It seems that it doesn’t actually take Ant-Man too long to escape from the other dimension and get back to full size.
Presumably, his return is what kicks off the plan that Steve and Nat are about to enact in the previous scene: they’ll use the Quantum Realm to dive into the past to reclaim the Infinity Stones. Unless that common theory’s wrong, too.