What can Apple TV do if I don’t have WiFi?

You will need internet connectivity and a home network (LAN) for Apple TV.

• The Apple TV app is used for online streaming content that requires an internet connection. Some content can be downloaded on some devices for offline viewing.
• The Apple TV set-top box is a streaming device, also relying on internet connectivity. It cannot download for offline viewing itself, but it can stream some content on local home network (e.g. files on a computer).

If you are in a remote rural location without internet, then you still may be able to stream some local files on a home network. Some content will still need an online connection, for authorization or streaming.

If you don’t have Wi-Fi, then maybe wired ethernet is an option. But consumer routers will regularly provide both options.