Chromecast with Google TV is getting the Stadia update
(Android Police)

... But Stadia is still not available It took an insanely long time for this to happen but Google`s cloud gaming service is finally being made available for the Android TV platform. In preparation for this, the Chromecast with Google TV is getting a new update that introduces support for Stadia among other improvements. The QTS1.210311.08 update weighs about 84MB and is already rolling out widely. Although it adds support for Stadia, the app is still not available to install from the Play Store. Read More Chromecast with Google TV is getting the Stadia update was written by the awesome team at Android Police.