Submission Underground 28 took place Sunday, October 31, 2021 with 10 fights in Portland, Oregon.

UFC 194: Aldo vs. McGregor was a mixed martial arts event held by the Ultimate Fighting Championship on December 12, 2015 at the MGM Grand Garden Arena in Las Vegas, Nevada. The event was headlined by a UFC Featherweight Championship unification bout between then champion José Aldo and then interim champion Conor McGregor.

UFC on ESPN 48: Strickland vs. Magomedov was a mixed martial arts event produced by the Ultimate Fighting Championship that took place on July 1, 2023, at the UFC Apex facility in Enterprise, Nevada, part of the Las Vegas Metropolitan Area, United States. A middleweight bout between Sean Strickland and Abusupiyan Magomedov headlined the event.

Eagle Fighting Championship 46: Lee vs. Sanchez was a mixed martial arts event held by Eagle Fighting Championship on March 11, 2022, in Miami, Florida, USA.

UFC Fight Night 112: Chiesa vs. Lee was a mixed martial arts event produced by the Ultimate Fighting Championship held on June 25, 2017, at Chesapeake Energy Arena in Oklahoma City, Oklahoma. A lightweight bout between The Ultimate Fighter: Live lightweight winner Michael Chiesa and Kevin Lee served as the event headliner.

UFC 216: Ferguson vs. Lee is a mixed martial arts event produced by the Ultimate Fighting Championship held on October 7, 2017 at T-Mobile Arena in Paradise, Nevada, part of the Las Vegas metropolitan area.

UFC Fight Night 128: Barboza vs. Lee was a mixed martial arts event produced by the Ultimate Fighting Championship that was held on April 21, 2018, at Boardwalk Hall in Atlantic City, New Jersey. A lightweight bout between Edson Barboza and former interim UFC Lightweight Championship challenger Kevin Lee served as the event headliner.

UFC on Fox 31: Lee vs. Iaquinta 2 was a mixed martial arts event produced by the Ultimate Fighting Championship that was held on December 15, 2018 at Fiserv Forum in Milwaukee, Wisconsin, United States. A lightweight rematch between former interim title challenger Kevin Lee and Al Iaquinta served as the event headliner. The pairing met previously in February 2014 at UFC 169 with Iaquinta winning the fight via unanimous decision.

UFC Fight Night 60: Henderson vs. Thatch was a mixed martial arts event held on February 14, 2015 at the 1stBank Center in Broomfield, Colorado.

UFC Fight Night 152: Dos Anjos vs. Lee was a mixed martial arts event produced by the Ultimate Fighting Championship that was held on May 18, 2019 at Blue Cross Arena in Rochester, New York. A welterweight bout between former UFC Lightweight Champion Rafael dos Anjos and former interim lightweight title challenger Kevin Lee served as the event headliner.