UFC 196 hosted the first fight between Conor McGregor and Nate Diaz.
The event took place on March 5, 2016, at the MGM Grand Garden Arena in Las Vegas. McGregor had originally been scheduled to face lightweight champion Rafael dos Anjos, but dos Anjos withdrew because of injury. Diaz accepted the bout on short notice, and the contest was made at welterweight.
Diaz submitted McGregor with a rear-naked choke in the second round after McGregor had success early with his boxing. It was one of the most significant upsets of McGregor’s career and gave Diaz a major victory over the reigning featherweight champion.
The rivals met again at UFC 202 later in 2016. McGregor won that rematch by majority decision, so UFC 196 is specifically the event associated with their first meeting, not their second fight.