The premise with which it will be presented "Batwoman" next October 6 is that Bruce Wayne has disappeared from Gotham leaving the city without Batman to protect her and forcing her cousin Kate Kane to seek her own identity as a watchman.
However, we know the same as the producers of the series, as confirmed by the showrunner Caroline dries to BatwomanTV. In a recent interview, the producer has confirmed that, although she has a couple of ideas about where Bruce Wayne has gone, has not yet decided on any. However, it does not seem bad to not commit to any explanation for now:
I have strong ideas about every detail of the series but This is one where I want the audience to feel the mystery, because it really is.
Other details are also given in the interview, such as that there is both Commissioner Gordon and Barbara Gordon (although we will not see either of them) and that there are no plans to bring Maggie Sawyer or Renee Montoya to the series, despite the love affair with Kate in the comics.
In the case of the first, it is because it has already been adapted in "Supergirl" and in the second one because he thinks until he leaves "Birds of Prey" He doesn't believe that from Warner Bros. they give their approval.
Via information | Batwoman TV