https://comicbook.com/anime/news/velma-max-cancelled/

In a since-deleted Instagram post background artist Davey Cummings indicated that the Velma: This Halloween Needs to Be More Special! was the last fans will see of the polarizing Mindy Kaling-led animated series. “Backgrounds I painted for Velma Halloween Special. So fun working with this crew," he wrote. "There will not be a season 3, but I hope I get to work with these amazing talented people again one day. GO WATCH VELMA HALLOWEEN SPECIAL ON MAX!!" Velma's cancelation has yet to be confirmed.

Velma officially canceled after two seasons (https://www.imdb.com/news/ni64876899/?ref_=nm_nwr_1#:~:text=Max%20has%20canceled%20its%20animated,final%20outing%20for%20the%20show.)

Max has canceled its animated series Velma after two seasons. The show's second season debuted in April, and a Halloween special that premiered on Oct. 3 marks the final outing for the show.