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One alternative is to subscribe to iCloud calendar with your Exchange/O365 email accounts or any Outlook account, and then sync the same accounts in Outlook for Mac. See details:
An error occurred while saving the commentJ Beda commented
Support for Google's calendar system was great, now if you can add Apple's calendar system we could just use the Outlook software and see everything in one place! How great would that be? Very great I must say!