Find your game directory (usually under SteamApps\common\Call of Duty Modern Warfare 3\players ).
Once enabled, you can use the key to open the interface and enter commands: god : Enables invincibility. noclip : Allows you to fly through walls. notarget : Makes you invisible to AI enemies. give all : Grants all weapons and full ammo. cg_fov [value] : Adjusts your Field of View. [How To] Unlock Everything in COD MW3 - Easy Method is the only stable
If you really want a console, is the only stable, safe, and active solution: you risk a ban.
There is no "patched" method to enable a standard developer console in the 2023 version of Modern Warfare III is the only stable
Do not use this in official VAC-secured multiplayer lobbies; you risk a ban.