Announcement of its phase 4 came without an Avengers movie. For many, it was a surprise. After all, every MCU phase had at least one film that had all the themes of that phase; however, this time, phase 4 ends with Thor: Love and Thunder.
The ground level, we have the Avengers reorganising themselves. The Falcon and the Winter Soldier will establish the new captain American, while others, Spider-Man 3, Hawkeye, and Ms Marvel will introduce the next generation of heroes, who are either going to supplement or replace the old guard.
Along with this, we also have the introduction of vampires as well as potential return at some point in the movie. Claims that at some point, life on earth will feature new characters out of which the older Avengers inspire some.
First, team-ups were primarily relegated to small moments. We saw cameos from other MCU characters occur in films, to name some, Ant-Man, Iron Man 2 and thor. But in regards to all-out crossovers, phase three bought these with Captain America: Civil War and Thor: Ragnorak. Hence, team-ups were not restricted to just the Avengers movie.
Some films became baseline instructions to new characters. Spider-Man didn’t appear in the MCU’s film, like the black panther, but rather appeared in the civil war. This indicates that a few movies will be used to introduce the fans to the new heroes.