Google promises a vast choice of titles.
Google states that 120 games are expected to launch on Stadia during 2020 (including a number of exclusives)
As of this moment, the cloud-based platform has only one exclusive, Gylt. The team promised at least 10 timed exclusives within the first half of the year.
"Looking at our upcoming lineup, we are tracking more than 120 games coming to Stadia in 2020, and are targeting more than ten games in the first half of this year alone that will be only available on Stadia when they launch," wrote the team. "We’re working with our partners to share more on those games soon."
As for other plans, the team wants to add support for 4k gaming on the Web, add further Assistant functionality when playing on the Web, add support for additional Android Phones, and set up wireless gameplay on the Web through the Stadia controller.
You can find more details here.