Warning: SPOILERS for DC's Legends of Tomorrow season 6, episode 4, "Bay of Squids".
DC's Legends of Tomorrow season 6, episode 4 drops the time-traveling superheroes into the Cuban Missile Crisis, and the Arrowverse series makes some subtle jabs at X-Men: First Class, which also placed the mutant heroes in the midst of the 1962 nuclear stalemate between the United States and the Soviet Union. "Bay of Squids" focused solely on the Legends back on Earth and didn't check in with Sara Lance (Caity Lotz), who was abducted by aliens and crashed on another planet.
X-Men: First Class was a prequel that rebooted Fox's mutant superhero saga into a new timeline. Set in 1962, First Class depicted how Professor Charles Xavier (James McAvoy) met Erik Lensherr (Michael Fassbender), who became Magneto, and how the two best friends, along with Mystique (Jennifer Lawrence), founded the original class of X-Men as a part of the CIA. The climax of the film saw the X-Men trying to stop Sebastian Shaw (Kevin Bacon) from instigating the Cuban Missile Crisis. After Magneto used his powers to stop the Soviets' launched nuclear missiles and stopped Shaw's Hellfire Club, the X-Men broke apart as Magneto decided to turn the missiles on the humans while Professor X tried to stop him. Their conflict resulted in World War III being prevented but Xavier was accidentally shot through the spine and permanently disabled. Magneto then took a group of mutants who sided with him, including Mystique, and left Xavier and his remaining X-Men.
Legends of Tomorrow did their own unique and bizarre spin on the Cuban Missile Crisis that resulted in Fidel Castro (Tim Perez) launching one nuclear missile at the White House, but thankfully, Mick Rory (Dominic Purcell) stole the warhead so that the missile only killed one rogue U.S. general when it crashed on the White House lawn. But the verbiage Legends of Tomorrow used throughout the episode, which saw an alien crash land in Cuba and captured by Castro's forces, cleverly called back to X-Men: First Class. Instead of an alien from outer space, Castro assumed the creature was one of "the CIA's mutants from North America", which is exactly what the X-Men were in their movie. Fidel assumed the Americans sent the "mutant" to Cuba to kill him. "Mutants" from the CIA was referenced several times in the episode and since "mutants" aren't a concept embraced in the DC Universe, the X-Men connotation was hard to miss.
A more subtle X-Men reference is the presence of Nate Heywood (Nick Zano) in 1962 Cuba. Nate was photographed in full superhero mode as Steel fighting off Cuban soldiers. Not only did Castro's army see Steel but the CIA acquired the photograph and put it into the hands of President John F. Kennedy (Aaron Craven). Although Colossus wasn't in X-Men: First Class, the presence of a superhero made of organic steel in a scenario where "mutants" were consistently referenced brought to mind the similarities between Legends of Tomorrow's Steel and the much more well known Colossus, who was played by Daniel Cudmore in the X-Men movies and by Stefan Kapicic in the Deadpool films.
Legends of Tomorrow giddily weaves pop culture references, including Marvel, into the Arrowverse show so the use of specific verbiage like "the CIA's mutants" sound like deliberate nods to X-Men: First Class's unforgettable involvement in the Cuban Missile Crisis. Of course, it was only a matter of time until the Legends got mired in the Cuban Missile Crisis themselves and put their own spin on this major historical event. It's amusing how differently DC's Legends of Tomorrow handled one of the most precarious moments of the 20th century compared to how Marvel's mutant superheroes also saved the world (and changed history) in X-Men: First Class.