Microsoft has started rolling out iCloud Photos integration into Windows 11. A new update to the Photos app in Windows 11 is now available, which will include the ability to link an iCloud Photos library straight into the built-in Windows Photos app.
Windows 11 users will need to update their Photos app from the Microsoft Store, & then install an iCloud for Windows app from the Store. They can then sign in to choose which photos or libraries automatically sync to the Photos app.