After January 31, 2020, you will no longer find the Cortana mobile app and Microsoft is removing the digital assistance from Microsoft Launcher in select regions. At this time, the US isn’t affected, but the countries that will have Cortana go away are Great Britain, Australia, Germany, Mexico, China, Spain, Canada, and India.
Here’s the full announcement from Microsoft.
To make your personal digital assistant as helpful as possible, we’re integrating Cortana into your Microsoft 365 productivity apps. As part of this evolution, on January 31st, 2020, we’re ending support for the Cortana app on Android and iOS in your market. At that point, the Cortana content you created–such as reminders and lists–will no longer function in the Cortana mobile app or Microsoft Launcher, but can still be accessed through Cortana on Windows. Also, Cortana reminders, lists, and tasks are automatically synced to the Microsoft To Do app, which you can download to your phone for free.
After January 31st, 2020, the Cortana mobile app on your phone will no longer be supported and there will be an updated version of Microsoft Launcher with Cortana removed.
As the company notes, Cortana is being integrated into Microsoft 365 productivity apps. Because of that, we suppose standalone Cortana experiences aren’t required.