My Hero Academia: Heroes Rising will likely be the last animated movie based on the immensely popular franchise.
At the My Hero Academia event Hero FES, Horikoshi is quoted by Comic Natalie (translated by Anime News Network) as saying, "There won't be a third film. Probably." He then went on to explain Heroes Rising would use one of the concepts he had wanted for the manga's last fight and would thus serve as a sort of finale.
There's no indication this would at all affect the manga or the anime, especially since the events of My Academia: Two Heroes is, according to Horikoshi, canon, but did not seem to have any obvious effects on either.
My Hero Academia follows the students of U.A. High School learning to use their Quirks, the series' word for superpowers. The primary focus of the series is Izuku Midoriya. Although initially "Quirkless," Midoriya inherits the power of One for All from All Might, the most powerful and respected hero.
My Hero Academia has been serialized in Weekly Shonen Jump since 2014, and there are over 230 chapters available. The series proved so popular that it inspired a spinoff, My Hero Academia: Vigilantes. Legendary Entertainment also has the rights to a live-action adaptation of My Hero Academia. It's likely Horikoshi's statement does not refer to that potential film.
My Hero Academia Season 4 will start airing October 12. New Season 3 dub episodes air Sundays on Toonami. My Academia: Heroes Rising releases December 20 in Japan.