CNN+ on Apple TV

Go to the App Store app on your Apple TV box (4th generation or later). Find the app of your choice. Select that. On the app Details page, use the Get button to install. You will then find the newly installed app on your Home Screen. Open the app. Find a Sign-in section. Enter your account credentials, to unlock the subscription features. Enjoy the app.

CNN+ is available through the CNN app on supported devices. Sign in with your CNN+ account credentials.

If you have an Apple TV box (4th generation or later, tvOS 14 or later), then you can install their app from the on-device App Store. Are your apps updated to the current version? Are you in the US? Is your Apple ID for the US?

If you have a third party device with the Apple TV app, then Apple and the Apple TV app aren’t involved with CNN/​CNN+ there. Search the App Store of that device’s manufacturer for app availability.