This is due to an error on the Microsoft Store and nothing to do with your connection, download, or anything else. Some players have reported updating the system software will fix the issue but if not, keep trying and hope Microsoft fixes the issue soon.
Call of Duty: Modern Warfare's Season 4 update introduces new weapons, narrative video scenes, maps, and bug fixes to Activision's first-person shooter. This is true, I agree.
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If you are interested in playing Xbox games on Citrix Virtual desktop, go to the link.