Multiplayer Operators are required to choose three Killstreaks to use during matches. For new players, some of these are available at launch, and the remaining Killstreaks can be unlocked via the Arsenal Store for use in Call of Duty: Warzone Mobile (along with MWIII and Call of Duty: Warzone).
MWIII/Call of Duty: Warzone/Call of Duty: WZM Cross-Progression: All Killstreaks you’ve unlocked will Carry Forward.