When CBS’s Supergirl series was first announced there were whispers that she could crossover to the Arroverse shows as they’re produced by the same people. Now it’s sounding like that won’t be happening due to legal reasons.
Andrew Kreisberg told THR:
“There’s always those late nights, delirious, semi-high on pizza where you’re like, ‘You know what would be really cool? If â€¦,’ ” Kreisberg said. “But right now there is no legitimate actual plan to bring [The Flash’s] Cisco [Carlos Valdes] onto Supergirl or to bring [Supergirl’s] Winn [Jeremy Jordan] onto Legends [of Tomorrow]. First of all, we donâ€™t even know if we could, legally. And quite frankly, just making the Arrow-verse, which is what we call Legends, Flash and Arrow work and then making Supergirl work, it’s enough of a challenge without having to add a fourth player.”
In the past there was talk that while the Producers may have liked the idea, CBS wouldn’t have it and didn’t want a character from one of their shows appearing on another network.