The CW’s line of DC shows are unlikely to crossover with the DC Universe original shows.
It appears that the widely celebrated Arrowverse and DC Universe original shows are not going to crossover according The CW‘s president, Mark Pedowitz
During The CW panel at the Television Critics Association conference, Pedowitz explained that there aren’t any discussions currently going on behind the scenes about a potential crossover between the two DC-based universes.
Now while this may seem like bad news for people who were hoping to see the characters come together it isn’t completely. The DC Universe original shows are still very much in their infancy at this time and have yet to all premiere and therefore could potentially crossover with The CW shows in the future once they’ve become more established. I doubt the showrunner for most of these productions Greg Berlanti has ruled out the idea, either. However, until we hear otherwise they are unlikely to crossover.