Sling TV has made changes over the last couple of years to its service. This includes changing the interface of the menu and channel guide, and adding basic DVR support for users.
What appears to be a new feature in its tvOS app on the Apple TV HD and Apple TV 4K is Picture-In-Picture support. This a feature that has been on its iPadOS app for a couple of years now.
tvOS has had Picture-In-Picture support since tvOS 13, but it was only available on the Apple TV app when viewing content users had purchased from iTunes or the Apple TV app.
Now when using Picture-In-Picture in the tvOS Sling TV app, users can navigate through the app and browse other apps already on their Apple TV too.
From the looks of it, this feature looks to work on both on-demand and live content on Sling TV.
Sling TV costs $30 a month for both the Sling Orange and Sling Blue plans. It can be streamed on the iPhone, iPod Touch, iPad, Apple TV and Mac.