https://techcrunch.com/2020/04/02/facebook-messenger-desktop-app-2/

Facebook Messenger is finally getting desktop apps almost 9 years after its debut. After seeing over a 100% increase in desktop browser audio and video calling, Messenger today releases its Mac and Windows desktop apps. They bring the same features as the browser version, but make it easier to keep your chat threads handy than having Messenger buried in one of many tabs.

Facebook originally announced the Messenger desktop apps at its F8 conference a year ago. But given the conference is cancelled due to coronavirus this year and users clearly wanted the desktop apps now, it made sense to launch them without a big press event.