Good evening AcademyVillage,
Welcome to the Apple Support Communities!
I understand you are having an issue with Outlook 2016 not syncing with iCloud calendar on your Windows 10 PC. The resources below will provide some updated information for iCloud for Windows 10. I've highlighted some key information here for you. Click on the link for complete details.
Get help using iCloud for Windows
"iCloud for Window 10 works with the May 2019 Update version of Microsoft Windows 10 and later versions of Microsoft Windows 10, and has better integration with Microsoft Windows.
If you are running the May 2019 Update version of Microsoft Windows 10, or later versions, Apple recommends iCloud for Windows 10.
If you have a Microsoft account, you can download iCloud for Windows 10. If you need to create a Microsoft account, you can create one on the Microsoft website.
When you install iCloud for Windows 10, it will uninstall any previous versions of iCloud for Windows for all users."
Get help using Outlook with iCloud for Windows
Take care.