Windows 10 Mobile tried to attract users by letting them run the same “universal apps” on both their PCs and handsets, but the concept failed to catch on.
The OS accounted for just 0.03% of the global market – based on smartphone shipments – between April and June, according to research company IDC.
At one point in time, Microsoft was aggressively paying Android developers to launch their apps on Windows store – but failed to create any differentiation.

Of course we'll continue to support the platform.. bug fixes, security updates, etc. But building new features/hw aren't the focus. ? https://t.co/0CH9TZdIFu

— Joe Belfiore (@joebelfiore) October 8, 2017

Source: Microsoft gives up on Windows 10 Mobile – BBC News