Jedi Blue

Jedi Blue is the name of an agreement between Alphabet (Google) and Meta (Facebook) Platforms that allegedly gave Facebook an illegal advantage in Google's ad auctions in exchange for Facebook's word that it would end its own ad service plans. https://en.wikipedia.org/wiki/Jedi_Blue

Header bidding emerged in 2017 as a new way for purchasers to buy ad space. It allowed advertisers to participate in auctions across multiple ad platforms (such as Google's). Facebook announced plans to become header bidding-compatible. This would allow Facebook advertisers to bypass Google's platform

In 2018, Facebook and Google came to an agreement, leading Facebook to retreat from header bidding

Facebook agreed to reduce its participation in header bidding in return for "information, speed, and other advantages" that would come from staying with Google.

Multiple U.S. states sued Google in 2020.