In time for the holiday season, Microsoft will introduce its Xbox Cloud Gaming (aka xCloud) service on Xbox One and Xbox Series S / X consoles. The xCloud integration will allow Xbox owners to simply press play on an Xbox Game Pass game and immediately start streaming it, allowing players to try the games before beginning the (often hours-long) download and install process.
More than 100 Xbox Game Pass games will be available as part of this initial xCloud integration, and Xbox players will be able to try the games while they wait for them to fully download. The xCloud integration will also allow Xbox players to join multiplayer games as soon as friends send an invite, avoiding the need to wait for the setup to complete.
Microsoft will also update the Xbox interface on Xbox One and Xbox Series S / X consoles by adding a cloud icon to show which games can be streamed instantly. Streaming will be supported in resolutions up to 1080p and 60fps, so the service won't be a full-fledged replacement for those with 4K TVs. So Microsoft is heavily marketing this service as a "try before you download" service.
Since this service will also be coming to Xbox One, this means that Xbox Series S / X exclusive games like Microsoft Flight Simulator and The Medium will soon be available on older Xbox One consoles as well. Microsoft hasn't yet given a release date for Microsoft Flight Simulator on xCloud, saying it will "happen in the future."
xCloud Integration will be available for Xbox Insiders this fall before a wider release, and Microsoft plans to announce testing details soon.