According to Deadline, it seems Season 4 is still in development in addition to the news today:
https://deadline.com/2024/01/mandalorian-grogu-movie-jon-favreau-lucasfilm-1235700326/
“It’s not yet been confirmed whether Pascal will reprise his role as the Mandalorian for the new film. At present, a fourth season of his hit series is also in development.”