With the macOS Sequoia 15.2 beta, Apple has revamped AirPlay, adding new options for sharing a more limited amount of information on the screen when AirPlaying to an Apple TV.
There are now options to show your entire screen, a specific window or app, or your extended display. Limiting AirPlay to a specific app allows a presentation or photos to be shared on the larger screen of a TV without allowing viewers to see all of the content on a Mac.
In the current version of macOS, Apple allows for mirroring a Mac's display to an Apple TV, but there is no option for sharing just a portion of a display.
macOS Sequoia 15.2 is in beta right now, with Apple planning to release it to the public in early December. The update also adds Apple Intelligence features like Image Playground and ChatGPT Siri integration.
Source: Macrumors