In the latest Windows 10 Insider build, Microsoft is testing a new hidden standalone Cortana app. The Cortana Beta app gives us a glimpse of the future for Microsoft’s personal assistant. Users can either enable hidden features using mach-2 or launch the app via the Run: dialog. The app is still very much in development and while fun to play with, users will most likely find bugs and other issues that make you want to wait until the app is officially released before you can play with it.
Source: https://www.bleepingcomputer.com/news/microsoft/new-standalone-cortana-beta-app-coming-to-windows-10-insiders/