https://wccftech.com/warzone-cheaters-might-have-a-harder-time-with-the-new-two-step-sms-verification/

We've previously covered the wave of Warzone cheaters that have plagued the latest Call of Duty Battle Royale game on PC, to the point that this phenomenon started affecting the crossplay functionality with consoles. Shortly after that, Infinity Ward announced changes to the matchmaking system to try and match Warzone cheaters together.

However, the battle against cheating is far from over and the latest step taken by the developers is to require two-step SMS verification for new players of the game. This is important because Warzone cheaters can usually just create a new account if they get banned since the game is free to play. Now that's going to be more difficult as they would have to activate a new phone number/line every time.