Well, we have the first news of casting in the next Ant-Man movie:

Marvel's Ant-Man 3 Casts Jonathan Majors in Major Role

From the article, the rumor is that Majors will be playing Kang the Conqueror. Which is significant for one character in particular- Cassie.

In the Young Avengers comics, Cassie Lang and Iron Lad had a mutual attraction. It was later revealed that Iron Lad was, in fact, a teenage Kang. So by bringing in an adult Kang here, I wonder if they will use Ant Man 3 to set up the Young Avengers- either for a movie of their own, or perhaps a Disney+ show.