Warning: The following contains SPOILERS for Superman and Lois season 2.
The Arrowverse Earth-Prime was meant to contain every superhero show on The CW following the Crisis on Infinite Earths event, but the Superman & Lois season 2 finale confirmed that it is set on an entirely different Earth, somewhere else in the new multiverse. This seems obvious in retrospect, due to a number of inconsistencies between the Earth of Superman & Lois and the new Earth depicted in other Arrowverse series. It also explained why Superman seemed reluctant to call on his super friends in the new Justice League for help, firmly establishing that this version of Superman is the only superhero on his world.
When Superman & Lois first premiered, it was presumed to be a spinoff of Supergirl. Tyler Hoechlin first played the Man of Steel in Supergirl's season 2 premiere, and Elizabeth Tulloch introduced Lois Lane into the Arrowverse during the Elseworlds event. Both actors went on to appear as multiple versions of Clark Kent and Lois Lane during Crisis on Infinite Earths, and Superman was one of the heroes who helped form a new team of heroes united to deal with global disasters. It was presumed that Superman & Lois would be the first new Arrowverse series to be set on the newly formed Earth-Prime.
Related: Superman & Lois Season 2 Narrowly Avoids An Old Arrowverse Story Trap
The Superman & Lois season 2 finale, «Waiting For Superman,» confirmed that it was set on an entirely different world, separate from Earth-Prime. This revelation came as General Sam Lane (Dylan Walsh) was trying to calm his panicking grandsons, who were worried about their father. General Lane told the boys that he had seen things they would not believe in his military
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