Apparently there is no room for Cortana either on iOS, where Siri dominates, or on Android, where the Google assistant is ubiquitous, so Microsoft has decided to stop supporting this application.
Microsoft has shut down its Cortana app for iOS and Android, the latest move to kill Cortana across multiple devices, including Microsoft’s own Surface Headphones.
At the moment the Cortana application for iOS and Android is no longer in the official stores, although it has not caught anyone by surprise, they already announced it in July 2020. The goal now is for Cortana to continue its evolution as a productivity assistant.
In a note they say:
As of March 31, 2021, Cortana content that you created, such as reminders and lists, will no longer work in the Cortana mobile app, but can still be accessed through Cortana on Windows. Cortana’s reminders, lists, and tasks are now available in the Microsoft To Do app.
Microsoft first released Cortana for iOS and Android in December 2015. The initial goal was to connect Windows 10 PCs and mobile phones, but this was not achieved due to huge competition with other digital assistants. Right now Microsoft no longer sees Cortana as a competitor to Alexa and Google Assistant, it approaches it differently.
That’s not to say that Microsoft doesn’t work on conversational artificial intelligence, as Cortana will continue to focus on an assistant that can enhance Microsoft’s business-centric offerings.