The Chromecast built-in application enables your Android smart television to play back video content shared directly from a phone, tablet, or a computer. Works with major services such as YouTube, Netflix, and Spotify.
App Description from Google Play
Google Cast is a technology that enables multi-screen experiences and lets a user send and control content like video from a small computing device like a phone, tablet, or laptop to a large display device like a television.
This app includes Chromecast built-in for Android TV.
Available and pre-installed only on Google approved Android TV devices.