In a recent blogpost the search giant Google has announced that Apple TV is now
globally available on Chromecast. Back in December of 2020 Google has said Apple
TV would be available in Chromecast along with Apple TV+ . In the early months
of 2021 it would be available to more devices. The app grants users access to
premium original Apple TV+ content along with regular iTunes Movies and shows.
The integration of the app gives access to voice commands that can be used for
Apple TV or Apple Originals.

In a blog post dated February 18, Director of Media and Entertainment for
Android and Google Play, Jonathan Zepp, shared that Apple TV app, including
Apple TV+, is now available on Chromecast with Google TV
[] globally.

Further support for the app on Google TV will be added later in the near future.
For now you can go to For You tab to check Apple TV content or go to the Apps

Goggle TV users can also watch their favorite iTunes shows and movies they have
previously purchased and along with family subscription pack, up to six family
members can share the subscription to Apple TV and Apple TV+.