Spectrum "Streaming" product

Honestly I don't if there are other news channels available on ATV 3. You may want to consider upgrading your ATV 3 if you want or need more content. The ATV 4 & 4K models are in a totally different league than an ATV 3.

it cannot, you should check to see if they have an app for Apple TV 4 or 4K. If they do, they will need to upgrade to a new Apple TV that has an App Store (the Apple TV 3's do not) and then you can add the Spectrum app. Sorry but Apple TV 3's are now old techology and do not have the ability to support newer functionality such as adding apps to it.