Jujutsu Kaisen has become one of the biggest anime and manga franchises, with its popularity marking it among the "Dark Trio" of shonen, anime alongside Chainsaw Man and Hell's Paradise. Its turn on the silver screen only increased its global reach, and the same goes for the series' movie entry. Of course, due to being an anime movie, it is of understandably questionable canonicity, as many big name anime movies tend to take place outside the story. Jujutsu Kaisen 0 arguably predates the main series in more ways than just the title.
Source：https://www.cbr.com/jujutsu-kaisen-0-canon/
