Please note: The Season Four Reloaded update will have a download size of approximately 22-36 GB for owners of the full version of Modern Warfare. Console owners must install a secondary download of approximately 3.5 GB, then reboot the game to access Multiplayer, if desired.
A reminder, console players can choose also to uninstall/remove other data packs (e.g. Special Operations), if no longer needed for a smaller overall file size. Check out this article for detailed information on uninstalling/removing other data packs.
Once the Season Four Reloaded update is fully completed, it should minimally increase the overall size of the full version of Modern Warfare.
Existing free-to-play Warzone players will have a download size of approximately 22-30 GB, once finished there will be a reduction to the overall size of the game on their machines.