Intelligent Tracking Prevention (ITP) by Apple is designed to detect and flag when a domain has the potential to track visitors across sites (it does not attempt to validate if the domain actually does track across sites). Once flagged, Safari limits that domain’s access to cookies and other possible tracking methods.
Over time, Apple has rolled out stricter iterations to ITP, positioning itself as a champion of user privacy and interests. Apple’s removal of user tracking by blocking third-party cookies and imposing limits to client-side cookies has affected the entire adtech world, making it difficult for marketers to retarget and correctly attribute users across the web.