CMMC Compliance with Cell Phones

Hello,

Can anyone provide some documentation on how to handle email being connected to personal cell phones? Is this not allowed anymore? Does that mean no employee is allowed to have their email connected to their cell phone to check emails throughout the day if you want to be CMMC compliant…

Im curious because a lot of employees who connect Office365 outlook to their cell phones, would this go against the rules? Not sure if CUI would actually be downloaded to the phone or not.