From the latest announcements released by Microsoft, the three applications of Skype for Business, Microsoft Teams and Yammer will all stop supporting on May 20, 2018.
In fact, before this, many third-party applications have already left, and gave up the development of the Windows 10 Mobile ecosystem, and now Microsoft's approach is only more eager to let it die.
Anyway, let us miss the Windows Phone, and for a long time in the future, it will be Android and iOS.