https://wccftech.com/cod-black-ops-cold-war-modern-warefare-warzone-share-progression-weapons/

The crossover between Call of Duty: Modern Warfare and Call of Duty: Warzone has been incredibly successful for Activision, and the level of integration will only get deeper when Call of Duty: Black Ops Cold War launches next week. Starting in December, all three games, Black Ops Cold War, Warzone, and Modern Warfare, will share a common progression system. Additionally, all weapons and operators from Cold War and Modern Warfare will be available in Warzone.

Here are some details on how progression, weapon, and operator sharing will work: