How can I retrieve my photos that has been deleted

iCloud Photos is a syncing service. Any photo you delete from a device where iCloud Photos is turned on will also be deleted from iCloud and from any other device connected to iCloud Photos. They are in the Recently Deleted album for 30 days. On your iPhone, open the Photos app, then tap "Albums" at the bottom of the screen, then scroll all of the way to the bottom to Recently Deleted.

Another way that photos may be on iCloud (if you don’t have iCloud Photo Library turned on) is via a backup of an iOS device. The only thing you can do with a backup is use it to restore a device or set up a new device. The contents of backups are not viewable at iCloud.com and if you delete a photo from a device it will not be included in future backups and will be lost.