Fortnite isn't on Microsoft's Xbox Cloud Gaming service because

Epic Games isn’t putting Fortnite on Microsoft’s Xbox Cloud Gaming service because it views the platform as a competitor. An Epic Games executive has revealed why Fortnite isn’t on xCloud.

Is Grand Theft Auto 5 to blame for the Xbox Cloud Gaming demand surge? - Xfire

How to play Fortnite Xbox Cloud Gaming on iOS and Android

How to check Xbox Cloud Gaming Server Status? Is it down or not?

How to use XCloud Gaming in any country on your Steam Deck

Playing Fortnite on (Xbox Cloud Gaming) I don't play fortnite but I wanted to see how it plays/runs : r/xcloud

Xbox

Fortnite Xbox Support

Microsoft could launch free, ad-supported Xbox Cloud Gaming plan - SamMobile

Microsoft and NVIDIA Announce Expansive New Gaming Deal

Cloud gaming still has many obstacles to overcome, experts say - Polygon