Facebook conducts a test of Messenger for macOS in selected non-U.S. markets. This is not a full launch, the developers are still collecting the feedback from users.
Messenger app has been already available for desktop via browser, but the key feature of the app would be group video calls. So the app aims to provide a seamless connection with family or co-workers, creating space for collaboration.
Messenger app will make it easier to share files and communicate via your personal computer.
Once again, this is a test, and the dates of the full launch are still not clear.