A Bat Signal that's been on for three straight years, and a Gotham that's forced to create a private defense team (Jacob Kane's "The Crows") in Batman's absence. This is the opening for the CW's new Arrowverse show Batwoman, and it sets the stage for Kate Kane's Batwoman to pick up the pieces left by her MIA cousin Bruce Wayne. Within the pilot episode alone, Kate learns that Bruce is actually the missing Dark Knight, and that he left an entire Batcave full of suits and tech behind. As Bruce's cousin, Kate is the only one capable of accessing Bruce's lair, and the show is ostensibly about her own journey to become a caped crusader. It does beg the question though — why is Batman missing in Batwoman, and will he ever show up in the show?
It's not that far-fetched of a question, considering that Superman appeared on Supergirl in the opening moments of Season 2. Though Batwoman, like Supergirl, is centered on a younger, more inexperienced woman filling the shoes of her larger-than-life cousin, Kate's story still involves much of Batman himself. Kate only returns to Gotham because Alice and the Wonderland gang attack the event where Gotham was planning to officially say goodbye to Batman, and Kate only puts on the suit because Bruce isn't there to wear it. It's Kate's familial connection to Bruce that leads to her figuring out how to even access the Batcave, and ultimately Lucius Fox's son Luke trusts Kate because he knows she's related to Batman. (She also strong-arms him into it, but y'know, she is Batman's cousin.)
While it's not revealed in the Batwoman pilot why Batman is mysteriously missing, the comics may provide some key hints. Batwoman becomes the lead of Detective Comics issue #854 because Batman is presumed dead. At the start of the issue, Batwoman meets with a Batman to discuss Alice and her gang, but it's implied that's actually the former Robin, Dick Grayson, who swapped out his adult Nightwing costume for the Batman one in Bruce's absence. Bruce is presumed dead because of the preceding "Final Crisis" crossover storyline, in which members of the Justice League witnessed the villain Darkseid killing Batman with his Omega Beams. Darkseid just killed a clone though, and the real Batman was zapped back to Neanderthal times. While Kate and Dick defend Gotham in the present day, Bruce figures out how to ride the time stream — pretty poorly, at first — and return home.
It's a wild storyline, but Bruce being trapped in the past is pretty crucial info for the Arrowverse, as there just so happens to be a team that specializes in time-hopping — The Legends in Legends of Tomorrow. Bruce bouncing around in time — and fending off tentacle monsters, the pirate Bluebeard, and the bounty hunter Jonah Hex — feels out of step with the tonally serious Batwoman, but it's one that fits in pretty neatly with the fun and nonsensical Legends of Tomorrow. Does this mean that Batman will eventually appear on Legends of Tomorrow? Possibly. In the comics, Batman is ultimately rescued by the Justice League and Rip Hunter, who featured in the early seasons of Legends of Tomorrow; though Rip is no longer on the show, it would be easy to swap in Sara Lance and her team for the same story.
When asked about Batman appearing on Batwoman, executive producers Caroline Dries and Sarah Schechter simply told CinemaBlend at San Diego Comic Con that "anything is possible," but they're playing it safe for now because "everyone in this room knows how strict DC is" with the Batman property.
"I think part of Kate's journey is not to just fill these abandoned shoes, but to find her home," Dries continued. "So, I think it's really important she has that time for all of us to spend with her and figure out what it means."
It's true — ultimately, Batwoman is Kate Kane's show, and introducing Bruce Wayne too soon would distract from, and even undermine, Kate learning how to be Gotham's new hero. If Batman is ever introduced, it's possible he'll just leave Gotham to Kate. Perhaps he'll even spend more time with the Legends instead — seeing Bruce in a comical, irreverent show like that would be an amusing change from how he's usually portrayed in films, at least.
Or maybe Batwoman will do away with that story entirely, and Bruce is off living the life that Christopher Nolan's Alfred dreamed for him in the film The Dark Knight Rises: sitting somewhere at a cafe in Florence with a wife and kids, drinking coffee, and not having a care in the world knowing that Kate's there to hold things down.