When you push a certificate out in a profile, the certificate is statically stored on a Mac. If you are delivering a certificate over the air and in a device profile that is seperate from the MDM payload then the Active Directory Certificate payload can enable automatic certificate renewals. You can enable automatic renewals with a defaults command (or manage the preference domain via MDM) using the following command:
defaults write /Library/Preferences/com.apple.mdm-client AutoRenewCertificatesEnabled -bool YES
Note: Because they’re already dymanic and all, SCEP payloads cannot be automatically renewed.