The title qualifies "Android TV" with a "Streaming Box" right after. Lots of service providers supply such a box to subscribers (similarly to how ISPs provide all-in-one firewall-router-modems.) Even then these are extremely cheaply made, underpowered and largely unmaintained internet connected devices. And indeed you can purchase one such box yourself (including with piracy features as described here,) but I'd be surprised if the vast majority of these devices aren't supplied by the service providers.