UFC 266 marks the second bout between Nick Diaz and Robbie Lawler, with their original contest happening all the way back at UFC 47 in 2004. To give an idea of how long ago that was, and what the landscape was back then, that PPV was an event headlined by the first ever fight between Chuck Liddell and Tito Ortiz.
Diaz was able to knock out Lawler in the second round of that contest, and both men have had stellar careers since both in and out of the UFC. Diaz went on to become a Strikeforce champion and huge UFC star, while Lawler had a much rockier stint in Strikeforce before turning a page and eventually becoming UFC champion from 2014-2016.