The anime and the film will adapt different story arcs
Aniplex has revealed this past Sunday that Fate/Grand Order is getting 2 animation projects, being both a Tv Anime and a film project.
The Anime will adapt the “Babylonia” story while the film covers the “Camelot” story arc.
Toshifumi Akai is directing the Tv anime at Studios CloverWorks. On the film side we have Production I.G. in the works.
Via: Anime News Network