Hi @testuser7 , Thanks for reaching out.
Applications using the latest Microsoft Authentication Library (MSAL) can do certificate-based authentication (CBA) on Android devices without the Microsoft Authenticator app.
However, to support YubiKeys with Microsoft Entra CBA, YubiKey Android SDK has been integrated into the Microsoft broker code which can be leveraged through the latest MSAL.
I would suggest you post this idea at the Azure Feedback Portal, which is monitored by the product team for feature enhancements.
Hope this will help.
Thanks,
Shweta
Please remember to "Accept Answer" if answer helped you.