There is always a new update pending for Windows, the next one will be Windows 10 20H1 and it has reached RTM (Release to Manufacturers) status. The 20H1 suffix indicates a release within the first half-year of 2020.
So there is no exact date yet. The news was announced by Microsoft watcher Zac Bowden in the Windows Central podcast (from 6:00 AM). The current builds in the Windows Insider Program will contain changes that will only appear after update 20H1.
Windows 10 20H1 reaches RTM status: build 19041 will roll out next year