Superman & Lois can finally have a proper Arrowverse crossover with The Flash in the latter’s final season. With The Flash ending, so is the Arrowverse, as The Flash season 9 has been confirmed to be its last. With every other Arrowverse show having ended, how The Flash season 9 will conclude has drawn considerable hype from the Arrowverse's fanbase.
When it began in early 2020, Superman & Lois was vague in whether it truly took place on the Earth-Prime of the Arrowverse. Superman & Lois’s season 2 finale would later make it clear, via a monologue from General Sam Lane (Dylan Walsh), that the series does indeed take place in a different universe from the Arrowverse. Despite that, the Arrowverse does not necessarily have to end without Superman & Lois having a role to play in it.
Per Sam Lane’s speech, the Man of Steel of Superman & Lois is the only confirmed metahuman hero on the show’s Earth. While Superman & Lois benefited by going solo, this also means that a crossover of some kind between Superman & Lois and The Flash could be mutually beneficial to both shows. Such an event would also be easy to facilitate by way of the Multiverse.
Superman & Lois & The Flash's Crossover Can Help End The Arrowverse
Having Tyler Hoechlin’s Superman meet Grant Gustin’s Flash could actually set up a fitting send off for The Flash and the Arrowverse with how both series have operated. The Flash’s powers make Multiverse-travel very easy to work into any story, with the CW’s Crisis On Infinite Earths event doing exactly and Grant Gustin’s Scarlet Speedster playing a central role to it. Meanwhile, Superman & Lois has been devoted to Multiverse stories in both seasons, with John Henry Irons (Wolé Parks) originating from another Earth, along with Superman & Lois season 2 heavily involving the Bizarro World and Superman's doppelganger.
Either by having Superman brought into the Arrowverse or having The Flash travel to Clark Kent’s world could tell a great last story for the Arrowverse’s Barry Allen. The Flash and Superman could team-up to defeat a threat menacing one of their worlds in a final epic tale of heroism for Gustin’s Flash. Hoechlin’s Superman, in turn, could also finally meet another hero with powers like himself, the two events being equally significant for both characters, while simultaneously wrapping up the Arrowverse.
The style of Superman & Lois made the show feel totally isolated from any Arrowverse series as soon as it began, but that does not mean that it is required to maintain that status completely. With The Flash gearing up for one final sprint, a Flash-Superman team-up with Superman & Lois's version of Kal-El could make for the Arrowverse's last great crossover event.