Lois isn’t the only iconic DC Comics character set to debut, and it’s entirely possible that her appearance will be connected to the other character. Kate Kane, a.k.a. Batwoman, will make her first Arrow-verse appearance in the crossover. Since The CW is reportedly considering giving Kate a Batwoman series of her own, expanding the Arrow-verse to consist of five shows, the odds are that Kate will have a more significant role in the crossover than Lois, although only time will tell. We technically don’t even know which Earth the Arrow-verse version of Batwoman will hail from. If she comes from Earth-38, perhaps Superman and Lois could be the ones to introduce Kate to the heroes we already know and love.
Source : https://www.cinemablend.com/television/2457586/the-arrow-verses-lois-lane-just-got-cast-and-we-love-it