Office 365 currently blocks .zip files that contain .exe, .pif, or .scr files. However, if a zip file sent to a PantherList, then the entire .zip file will be blocked regardless of whether or not it contains an .exe, .pif, or .scr file.
For example, a .zip file with a bunch of Word documents sent to a PantherList will be blocked.
Someone wishing to send .zip files that do not contain .exe, .pif, or .scr files should send to individual addresses only. A person could use an Office 365 Contact Group as an alternative to PantherList. To learn how to create a contact group, read the following document - https://kb.uwm.edu/page.php?id=59520