It's kinda hard to explain and it gets covered in great detail in the first two games. But basically Ys is an ancient land that once was part of the world, but is now basically a floating island.
Call of Duty: Warzone 2.0\n\n The full game is free to play, though players can buy Season Passes to acquire rewards such as new weapons and Operators. Players can progress through each Battle Pass through Warzone 2.0 and/or Modern Warfare 2.