cannot see iCloud Photos in iPhoto

"iPhoto" doesn't support iCloud Photos; you need the newer "Photos" app for that.

What macOS version do your have on your Mac?

What model (MacBook Air, iMac, etc) and what model year is it?

All 3 of the above are available at Apple menu > About This Mac.

If you have iCloud Photos turned on, the photos on the device are the same as on iCloud, with the possible exception that some of them may be space-saving optimized versions if you have that option turned on. You view them in the Photos app on an iOS device or Mac. You can also login to icloud.com and go to the Photos app there. The following Apple article has information about iCloud Photos: Set up and use iCloud Photos - Apple Support

If you didn't have iCloud Photos turned on but do have an iCloud backup, you can restore the entire phone (not just the photos) from iCloud but you cannot otherwise view the contents of the backup. The following Apple article has information about backup: Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

1. Can you see the photos in an internet browser on your Mac if you log into iCloud.com?
2. If yes to #1 above, if you open the Photos app on the Mac, click Library in the sidebar and then scroll to the bottom of the Library in the main window, what does it show for the syncing status?