Xbox is testing two new ways to play cloud games, one of which doesn't require a physical controller at all.
On November 4th, the official Xbox blog, Xbox Wire, announced a preview feature for a mobile virtual controller. This feature will be rolled out to compatible smart TVs in all regions covered by Xbox Cloud Gaming. Both Android and iOS devices support this feature, allowing players to use their phones as controllers when "no controller is nearby." Simply pair your phone with the TV using a QR code, and the control interface will open in your phone's browser.
The second preview feature, called "Cloud Connect," is currently only available in the United States. This feature allows the new Xbox Nano controller to connect to cloud gaming sessions via Wi-Fi instead of pairing directly with the TV. Microsoft claims this reduces input lag and makes controls more responsive.
To try out the mobile virtual controller feature, simply update to the latest version of the Xbox Smart TV app and enable "Preview Features" under "Settings > Account."
Xbox has released a complete setup guide. However, it's important to note that both features are "currently in beta," so as Xbox collects user feedback for optimization, the availability, supported games, and devices "may have certain limitations."