The latest update to Stadia added an interesting new feature: Tandem Mode. This allows users to connect a secondary controller to the USB-C port on the Stadia controller, with the input working for both at the same time. Don’t get too excited, though: the feature is meant to be an accessibility tool, not an easy way to add multiplayer.
That said, it̵7;s a cool idea if you’re having trouble using a regular game controller. Stadia’s support documentation explicitly mentions the Xbox Adaptive Controller, a gadget designed with incredibly varied input options. Pressing buttons on the secondary connected control unit will mimic the same buttons on the Stadia control.
Other Stadia controls and controls from Xbox One and PS4 also work (as long as you have the right cable or adapter), which can be a great way to help extremely young children play. Multiple Stadia controllers can use Tandem mode at the same time, as long as they are connected to Stadia wirelessly.
Google is very clear that this is an experimental feature, so it may change … or disappear completely. Stadia’s features are a bit fluid at the moment, but it shows some of the unexpected things the Wi-Fi-based controller can do.
Source: Google via 9to5Google