When Stadia was unveiled at GDC last year it was said eventually the platform would be able to do 8k 120 fps. In a tweet the official Stadia account has reconfirmed that they are looking to bring that standard to the platform. Both the Xbox Series X and PlayStation 5 have both indicated that they will able to support 8k 120 FPS. It is however unlikely that we will see many if any games support this.
With Stadia again reaffirming this is a good sign and shows the power of the platform as it every evolving. We should not take this news as it is coming soon more a reminder that Stadia will get better in the future.