If you missed iOS 12.2, your iOS 12.3 update brings additional improvements to AirPlay.
On iOS 12.2/iOS 12.3 you now get dedicated TV controls in Control Center and on the Lock Screen. These give you quick access to your TV controls.
AirPlay multitasking for video now allows you to browse other apps, as well as play other short form audio and video files locally on your device without interrupting AirPlay.
Your AirPlay destinations are also now grouped by content type which will help you quickly find what device you want to play to.
In addition, you can now Ask Siri on your iPhone or iPad to play any video, show, movie, sports game, or channel on Apple TV.
If you're a heavy AirPlay user, you'll want to install the latest firmware.