Supergirl as she appeared portrayed by Sasha Calle in The Flash becomes a part of the Injustice 2 Mobile roster as a Gold Fighter. This is more than just a skin for Supergirl, the Girl of Steel comes with all new stats and moves as a support hero.
Injustice 2 Mobile still receives updates compared to its console counterpart from 2017. The game saw the inclusion of Supergirl in the main campaign as a major addition to the fighting game. With the release of The Flash, it seemed natural that a skin or character of her from the movie would appear in-game. After all, Injustice released a Man of Steel pack in 2013 that featured Superman and General Zod skins.
The Flash’s Supergirl can be obtained in-game with the new Last Daughter of Krypton pass.