There is no official Call of Duty: Black Ops 4 (BO4) game available for Android
While many sites claim to offer a Call of Duty: Black Ops 4 APK + OBB for Android, no official standalone mobile version of this specific title Call of Duty: Black Ops 4 was released exclusively for PlayStation 4 Windows PC Call Of Duty Black Ops 4 Apk - Obb For Android