Seems to be quite huge on Game Pass.
Already 63k people on TrueAchievements played the game.
To put that into perspective, some other shooters that are or were at one point on Game Pass:
Wolfenstein: Youngblood: 47k
Metro Exodus: 86k
Doom Eternal: 105k
World War Z: 120k
Depending on the pace, 100k shouldn't take too long.