Channel 4 app on apple tv

While the All 4 app is currently not listed as available in the tvOS App Store, it is available for iPhone, iPad and iPod touch, and it does support AirPlay to an Apple TV.

The 4K Apple TV has an App Store. You can look for Apps there to add to your Apple TV.

Apps for specific 3rd party channels are not pre-installed.

If the App for the channel or media provider cannot be found in the App store, contact the Channel or developer. Its entirely up to them whether a version for the Apple TV is available or not.

Download apps and games using the App Store - Apple Support