This is no small news! The Hollywood Reporter broke the news that Ant-Man 3 has been added to the Marvel Studios schedule. The report also says that Peyton Reed will return to direct. Paul Rudd will also be back as Scott Lang. Those are the only two names that we know at this time.
It’s hard to believe that Evangeline Lilly would not return. In a post Endgame MCU, however, anything is possible. As far as a release date goes, it appears that will be sometime in 2022. That means that Ant-Man 3 would join Black Panther 2 on the release slate that year.
I will update you as the story develops.