@Dylan Berghuis, Thanks for posting in Q&A.
I have done some research about this issue, and currently Cloud PKI only supports devices managed by Intune, like Windows, Android, iOS, macOS. And due to the DC exists in Windows Server, Cloud PKI doesn't support Windows Server, so it doesn't support Smartcard authentication.
https://learn.microsoft.com/en-us/mem/intune/protect/microsoft-cloud-pki-overview
However, this function maybe in the future will be applied to Windows Server.
Thanks for your kind understanding.
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