Valve has touted the Steam Controller as a gamepad that works well with PC games made to be controlled with a mouse and keyboard. In an interview with IGN last June, Firaxis said it was optimizing XCOM 2 for mouse-and-keyboard controls: The interface is text-heavy, and the game is designed to be played at a desk, where you're sitting close enough to a monitor to read everything. XCOM 2 doesn't currently support any other controller, perhaps because Valve worked with Firaxis to build Steam Controller compatibility into the game.
'We consider this configuration to be an initial implementation, and as always, we hope the community will provide feedback in addition to making improvements to the configuration on their own,' said Valve. In addition, the touchpads can be used to adjust the camera in the Geoscape and tactical view. XCOM 2 players can use the Steam Controller to play the game with situation-dependent control configurations, using the gamepad's touch menus to select abilities.