Picking up shortly after the events of Avengers: Endgame, the world is grieving the loss of Tony Stark. Peter, on his way to a summer vacation in Europe, is tracked down by Nick Fury and recruited to take down monsters that will destroy the Earth. Making friends with Quentin Beck (Mysterio), they work together to stop this looming threat.
In the post-credit scene, we learn that Nick Fury (Samuel L Jackson) and Maria Hill (Cobie Smulders) were not actually Nick Fury and Maria Hill. Instead, they were the shapeshifter Talos (Ben Mendolsohn) and his wife, fellow Skrull shapeshifter Soren in disguise. After reverting to their normal green alien form, Talos makes a call to Fury to fill him in on how everything ended up going with Mysterio. Fury, it turns out, was actually out on a spaceship somewhere with a bunch of Skrulls, doing who-knows-what.
Not sure what this scene means yet, but it’s probably safe to guess it has something to do with Captain Marvel 2, since the first movie is the one that introduced the Skrulls to the MCU.