Works just like HBO Go, log in to your cable subscriber and all their content is on demand, Or in my case it already knew I had fios subscription, asked for access and boom it had it.
https://www.macrumors.com/2018/06/22/watch-tcm-app-launches-tvos/
https://www.macrumors.com/2018/06/22/watch-tcm-app-launches-tvos/