Mozilla recently added a feature that enhances privacy protection in Firefox browser to help prevent online advertisers from tracking across the web. This feature is called first-party isolation (first-party isolation), originating from the Tor browser. The Tor browser is based on Firefox’s long term support and incorporates a large number of privacy protection features. When we visit a website, the website will leave a tracking cookie on your browser, but in addition it will leave cookies from third parties, and if you visit another site that has this cookie, the third party will be able to track your activities on two of websites. The so-called first-party isolation is a cookie left by a website that is isolated from another cookie, leaving a third-party cookie unable to track across the web.