Sad to say but Microsoft already shut down the Cortana mobile app on both Android and iOS devices. What is Cortana? It is Microsoft’s version of Siri or Alexa. It is an Artificial Intelligence-based personal assistant that you can address questions and complete a small task.
Cortana is originally a Windows 10 feature but introduced in mobile in November 2018. Microsoft announced in July 2020 that they will shut down Cortana in Android and iOS this March 31, 2021. It’s now no longer supported by Microsoft and no longer available in Google Play Store and App Store. So, reminders and lists are also no longer available to users through the Cortana mobile app.
But they can still have access to them through Cortana on Windows. Besides, Cortana reminders, lists, and tasks are automatically synced to the Microsoft To Do app. Microsoft To Do is available for free on both Android and iOS devices.
They shut it down because Microsoft would shift toward a “transformational AI-powered assistant experience” in its Microsoft 365 apps. Which would include pulling together its areas of advancement and improvement.
Source: Microsoft Support