Apple has recently introduced the iCloud Private Relay which helps users to browse anonymously using the Safari browser. It mimics the functionality of a proxy server which is normally used to shield the identity of the user from the destination website.
https://support.apple.com/en-us/HT212614
Detecting iCloud Private Relay IP addresses using IP2Location database
To check whether the IP is part of the iCloud Private Relay, you just need to read the ISP column in the IP2Location IP geolocation database. If the ISP value is “iCloud Private Relay” then that IP belongs to the iCloud Private Relay.
Detecting iCloud Private Relay IP addresses using IP2Proxy database
To check whether the IP is part of the iCloud Private Relay, you just need to read the ISP or Provider column in the IP2Proxy Proxy Detection database. If the ISP or Provider value is “iCloud Private Relay” then that IP belongs to the iCloud Private Relay.
Disclaimer
iCloud is a registered trademark of Apple Inc.