Activision frequently runs limited-time "Free Access" events, often around new season launches. During these periods, you can download a trial version from the PlayStation Store , Xbox Store , or Battle.net that typically includes a selection of Multiplayer maps and the full Zombies mode.
If you plan to download the game during a free trial or via Game Pass, ensure your PC meets these minimum specs: Call of Duty® - Free download and play on Windows Call of Duty: Modern Warfare 3 Free Game Downlo...
There are a few ways you can occasionally play portions of the game without buying it: PC System Requirements
If you have an active Xbox Game Pass Ultimate subscription, the game is included as part of the service, meaning you don't have to purchase it separately. PC System Requirements Call of Duty: Modern Warfare 3 Free Game Downlo...