Roku press release:

For the first time ever, Roku users can add the Apple TV app via the Roku Channel Store to discover and watch movies, TV shows and more, including accessing their iTunes video library and subscribing to Apple TV channels directly on Roku devices. Starting November 1, Apple TV+, Apple’s home for all-original shows and movies from the world’s greatest storytellers, will be available on the Apple TV app on the Roku platform.

Even with the absence of a back catalog, Apple TV+ is playing the long game. Lots of press and chess moves, all backed by a long term war chest to take on Disney+, Netflix, HBO, and others.