Ubisoft has made most of its gaming catalog available to all popular game streaming services in 2022, That's about to change with Assassin’s Creed Mirage. Ubisoft has confirmed it will not stream the latest title coming to the Assassin's Creed franchise on Google Stadia, instead electing to sign an exclusive agreement with Amazon Luna.
Google and Ubisoft have always had a close partnership. When Stadia was in the technical testing phase known as Project Stream it was Assassin’s Creed that provided the experience. Ubisoft+ is also available on both Stadia and Amazon Luna as well as GeForce Now if you own the titles. The major issue for Amazon Luna isn't the devices you want to play the title on, but that Amazon Luna is only available in the United States.
So if you're not in the United States and on Amazon Luna you're out of luck for now if you want to stream Assassin's Creed Mirage.