Kyle “Gaz” Garrick is a staple in the rebooted Modern Warfare series and seems fitting that there are multiple ways to unlock his character and skins. There are two methods to unlock Gaz:
Completing the Atomgrad Special Ops Raid and buying the bundle will unlock a bonus Grass Ops skin, but requires doing both to receive the bonus skin.
Klaus Fisker, who is new to the Call of Duty universe and suspiciously mimics Santa Claus, can only be unlocked in one method. Klaus is available in the Tracer Pack: Klaus Operator Bundle from the in-game store. The bundle features the unlockable character, two weapon blueprints, and other festive cosmetic items.