That highly anticipated feature is finally showing signs of life, albeit in a very limited form.
Similar to the Windows Subsystem for Linux, the Android subsystem will run in a Hyper-V Virtual machine.
These seem to be integrated pretty tightly with Windows.

Unfortunately, the selection is very limited to start, at just 50 apps.
These include Amazons Kindle app, Khan Academy Kids, and a handful of games and apps for kids.