Regarding purchased content in Warzone Caldera  from Modern Warfare (2024), Black Ops Cold War, or Vanguard  that will continue to be accessible in those specific games.

Each game is set in a completely different time period. Modern Warfare 2 is set in the present day, while Vanguard is set in the midst of World War 2 - this means all the weapons, vehicles, and maps are completely different.