https://www.theverge.com/2019/1/3/18167304/charter-spectrum-app-apple-tv-login

An official Spectrum TV app has been released for Apple TV customers after delays pushed back Charter’s planned 2018 launch for the app into the new year. The free app is straightforward, allowing subscribers to watch Spectrum programming — both live channels and on-demand content — when an Apple TV is connected to Spectrum home internet service without requiring the customer to sign in with their account details.

To use the new Spectrum TV app, you’ll need an active Spectrum TV / internet subscription and a fourth-generation Apple TV (or the Apple TV 4K).