The newest update of Firefox – Firefox 63 – comes with a new feature called Enhanced Tracking Protection. This feature prevents against privacy-invading cross-site tracking cookies. This feature blocks cookies and storage access from the third-party cookies that are most commonly associated with privacy-harming behavior.

To enable this feature in your Firefox browser, enter your Privacy & Security settings and click on Content Blocking then check the box labeled “Third-Party Cookies”.

The one downside to this feature is that it can cause some sites to crash. However, you can disable the blocking on a site-by-site basis.

Other new features coming with Firefox 63 include the ability to have the browser mimic the light or dark theme used by the operating system, and Siri shortcuts for Firefox on iOS (for you Apple fans).

Source: https://thenextweb.com/tech/2018/10/23/firefox-63-will-prevent-cookies-tracking-you-across-sites/