The Razer Kishi controller is the best way to experience Project xCloud
The Razer Kishi is clip-on controller compatible with a huge range of Android phones that support USB-C. This is why I think it
Razer Kishi for Android (Xbox) Review
Razer's Kishi is the Switch-style phone controller I've been waiting for
Razer Kishi V2 review: Perfecting Xbox Cloud Gaming on Android : r/XboxSeriesX
How to use Razer Kishi with Project xCloud and Game Pass Ultimate
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Xbox Game Pass on phone can give the Switch a run for its money - in the right conditions
Razer Kishi Gaming Controller Review 2020 - Best Nintendo Switch Alternative
Microsoft provides details on Project xCloud's games, and its controllers
Apple Begins Selling Razer Kishi Gaming Controller for iPhone, New Mophie Charging Stands, and More - MacRumors
These Are The Xbox Project xCloud Launch Controllers - SlashGear
Razer Kishi for Android (Xbox) Gaming Controller: Cloud Gaming Ready Compatible with Most USB-C Android Phones Black RZ06-02900200-R3U1 - Best Buy
Hands On: Project xCloud Works Almost Impossibly Well
Android Gaming Controller S22 Ultra Review, by Gadget Guy