The next My Hero Academia movie is currently in development. Crunchyroll detailed that during the AnimeJapan 2019 event TOHO animation announced the new My Hero Academia movie. Their second feature film will release in Japan at the end of this year, however, there has been no mention of an international release yet.
— 僕のヒーローアカデミア "ヒロアカ"アニメ公式 (@heroaca_anime) March 23, 2019
Kohei Horikoshi, the author of the My Hero Academia manga will once again be in charge of original character design and story. Just like the first film, Kenji Nagasaki will return as the director along with Yosuke Kuroda’s screenplay.
Also, Kohei Horikoshi shared an illustration for the second film’s announcement:
The image shows All-Might, Midoriya, and Bakugou which may suggest that these three will be the primary characters in the upcoming film. Even though it is still unclear when the movie will take place, this image may have hinted it with their outfits.
The suits Midoriya and Bakugou are wearing are from the Provisional Hero License Exam Arc, however, their suits do change later on in the Joint Training Arc. The gap between those two story arcs is quite large so it is possible for the movie to take place around season 3 or early on in season 4.
The first film My Hero Academia: Two Heroes released last summer. The 4th season of My Hero Academia will arrive in October 2019.