From Google:

For many years, Google has invested across multiple aspects of the gaming industry. We help developers build and distribute gaming apps on Google Play and Google Play Games. Gaming creators are reaching audiences around the world on YouTube through videos, live streaming and Shorts. And our cloud streaming technology delivers immersive gameplay at massive scale.

A few years ago, we also launched a consumer gaming service, Stadia. And while Stadia's approach to streaming games for consumers was built on a strong technology foundation, it hasn't gained the traction with users that we expected so we’ve made the difficult decision to begin winding down our Stadia streaming service.

We’re grateful to the dedicated Stadia players that have been with us from the start. We will be refunding all Stadia hardware purchases made through the Google Store, and all game and add-on content purchases made through the Stadia store. Players will continue to have access to their games library and play through January 18, 2023 so they can complete final play sessions. We expect to have the majority of refunds completed by mid-January, 2023.

The underlying technology platform that powers Stadia has been proven at scale and transcends gaming. We see clear opportunities to apply this technology across other parts of Google like YouTube, Google Play, and our Augmented Reality (AR) efforts — as well as make it available to our industry partners, which aligns with where we see the future of gaming headed. We remain deeply committed to gaming, and we will continue to invest in new tools, technologies and platforms that power the success of developers, industry partners, cloud customers and creators.

For the Stadia team, building and supporting Stadia from the ground up has been fueled by the same passion for games that our players have. Many of the Stadia team members will be carrying this work forward in other parts of the company. We’re so grateful for the groundbreaking work of the team and we look forward to continuing to have an impact across gaming and other industries using the foundational Stadia streaming technology.

To summarize:

• Players will continue to have access to their games library through January 18, 2023 so they can complete final play sessions and move their progress to alternate platforms where possible.
• Commerce functionality (the ability to buy games, new subscriptions, add-ons or in-game purchases) on Stadia has now been disabled.
• Google will offer a full refund of all Stadia hardware purchases (Stadia Controller, Stadia Founder’s Edition, Stadia Premiere Edition, or Play and Watch with Google TV Package) made in the Google Store and all purchases of games and in-game transactions made in the Stadia Store.
• The refund process will take some time to complete, and Google expects to have the majority of refunds completed by the middle of January 2023.
• Stadia Pro subscription payments will not be eligible for refund, but if you are an active subscriber, you will continue to have access to your library without charge during the shut-down period.

Really, this comes as no surprise, as Google has been slowly shutting down stadia development for a while, I enjoyed playing it though and even though I knew they'd eventually kill it, it's still sad.