Valve announced an app it will be launching soon called Steam Link. It will let you play Steam games on iOS and tvOS. But there’s a catch.
In order to play Steam games on iOS and tvOS, you’ll need a 5Ghz Wi-Fi network or a wired Ethernet connection to your Mac. This means that you won’t likely be playing games on the go.
Steam Link will launch in a couple of weeks, and will include support for the Steam Controller and Made for iPhone controllers. Later this summer a Steam Video app will launch, letting you play Steam movies on your iOS devices over Wi-Fi or LTE.