Pitch Perfect was a success story upon its release, but after three films, a fourth never happened. Pitch Perfect released in theaters in September 2012 and, after several months, grossed over $100 million at the global box office, and became a staple of cable television airings. The film’s popularity led to two sequels, Pitch Perfect 2 in 2015 and Pitch Perfect 3 in 2017, with the latter taking place after the Barden Bellas graduated from college. With both sequels surpassing the original film’s box office numbers, it seemed likely Pitch Perfect 4 would happen — but it surprisingly has not.

https://screenrant.com/why-pitch-perfect-4-movie-never-happened/