Maul was expanded upon greatly in The Clone Wars, returning with a robotic lower half after Obi-Wan Kenobi sliced him in two. Maul’s story continued in Star Wars: Rebels, another animated series that took the story forward between the events of Revenge of the Sith and A New Hope.
During it, Maul was once again killed off by Obi-Wan (voiced by James Arnold Taylor), bringing the villain’s storied arc to a definitive end. At least, so fans thought, as the potential return of the Crimson Dawn also invites the possibility of the Dathomirian Sith’s return.
There are several ways this could be explained, with him simply surviving his duel being the most obvious. He survived before, so it wouldn’t be out of the realms of possibility. However, there is a more outlandish theory that could bring him back in The Book of Boba Fett – time travel.