Warning: SPOILERS for Ant-Man and the Wasp are ahead!
While each entry in the Marvel Cinematic Universe is important in its own way, some are more self-contained than others. Two months after Avengers: Infinity War resulted in half of the universe being wiped out, Ant-Man and the Wasp wound the clock back a little bit to show what Scott Lang, Hope van Dyne and the rest of the people in their circle were up to after Captain America: Civil War, but before Thanos snapped his Infinity Stones-powered fingers. The main story definitely stood on its own, but then the mid and post-credits scenes decided to address the Mad Titan in the room, and a new Ant-Man and the Wasp video throws in a nod to that.
Ant-Man and the Wasp is wrapping up its time in theaters, which means that it won't be much longer until you can watch the movie in the comfort of your own home. The above Marvel video announces that the movie will drop on home media next month, and it functions as a standard trailer, albeit showing some scenes that were kept secret during the theatrical promotion. But at the very end, everything on the screen quickly fades away, and that effect looks an awful lot like the dust effect that we saw when folks faded away at the end of Avengers: Infinity War. For folks who haven't seen Ant-Man and the Wasp, this effect probably doesn't mean anything, but those who have seen the movie, they know this is a quick reference to what goes down in the final minutes.
In case you need a refresher, Ant-Man and the Wasp's mid-credits scene picked back up with Scott, Hope, Hank Pym and Janet van Dyne at the exact time that the battle in Wakanda was unfolding in Avengers: Infinity War. Scott entered the Quantum Realm to harvest some quantum energy that would help Ava Starr's condition, and he was only supposed to stay there for a few minutes. Unfortunately for him, soon after he traveled to that other reality, Thanos carried out his genocide, and Hope, Hank and Janet were among the unlucky ones who disintegrated. Scott is still intact, but now he's stranded in the Quantum Realm, and it remains to be seen how he'll escape, although many have speculated it will require him to go through one of those time vortexes that Janet told him to stay away from. And for those wondering, Ant-Man and the Wasp's post-credits scene showed that the giant ant that wore Scott's house arrest ankle bracelet survived the Thanos snap, as it continued drumming away without a care in the world.