appel tv

it's like an ipad that use your tv as display the only stuff it can display is apps that stream from the internet or from a shared lib on your network, it does not support air broadcasted or cable broadcasted or sat disc broadcasted media, so if your national tv has an app (mine do) you can download that from app store and watch live tv from the internet

All content on Apple TV is delivered through apps. If your national TV network has published an app for Apple TV, then you can watch their content on this device. If a third party app developer has published an app for Apple TV that supports your national TV, then you can watch their content on this device. National TV may or may not require a subscription with a TV provider.

The media landscape and how it is organized, differs a lot per country. For which country are you inquiring?