Hello @Hammer
Since it's published by Bethesda, which is owned (through ZeniMax) by Microsoft, I would be fairly surprised to see them bring this to Stadia. I'd love to end up being wrong, but I'm not holding my breath.
Hello @Hammer & @JohnZoidberg,
As Elder Scroll Online is on Stadia and as Skyrim has been ported into many different devices (PS3, PS4, Nintendo Switch, Xbox 360, Xbox One, and also PS5 & Xbox Series X), this wouldn't, personally, surprise me. Also, Serious Sam is on Stadia too.
But you have to know that Bethesda & Zenimax has been acquired by Microsoft on September 2020, and with the launch of XCloud.. well, we will see.
In all case only Zenimax/Bethesda or Microsoft are able to make an official communication on it - not Stadia, sadly.