Microsoft has been teasing Edge for Linux for some time now, and in September even ran a survey asking amongst other things if there was a demand for the browser there.
Edge is already available on iOS, Android, Mac, Windows 10 and Windows 7. Now at Ignite 2019 Microsoft explicitly confirmed Edge for Linux is coming in the future.
Having the browser available on the open-source operating system would make it easier for developers using the operating system to create web sites and web apps which are Edge-compatible, making it an advantage for Microsoft despite the rather small potential audience.
It is not clear when “the future” is, but it appears likely it will be after the new Edge for Windows will exit beta.