https://www.pcgamer.com/epics-unreal-engine-support-for-stadia-is-already-live/

The big news out of GDC today is Stadia, the cloud gaming service that Google says will launch later this year with support for 4K resolution at 60 fps. The biggest (and, I think, only) game announced for the platform at this point is Doom Eternal, but Google has also joined with Unreal and Unity to "bring full support to the most popular and familiar game engines to our development community." 

In fact, developers can take advantage of one half of that partnership right now, as Epic has announced that Unreal Engine support for Stadia is already available. The engine will enable developers to dive into Stadia's new features "through familiar interfaces," and to iterate locally before deploying to the cloud. And because Stadia is entirely cloud-based, playtesting is simply a matter of sharing a link.