Arrowverse: 10 Implications From Crisis On Infinite Earths
4. Supergirl Is Now On Earth Prime
Supergirl always had an interesting history within the Arrowverse due in part to the fact that it started on CBS as opposed to the rest of the shows which were airing on the CW. This meant that it was placed on Earth-38 as opposed to the rest of the main Arrowverse taking place on Earth-1. Initially this meant that the team had to engage in some cross-dimensional acts in order to get Kara and/or Clark to take part in the annual crossovers.
With the rebooting of the universe, the Supergirl cast and show have now been folded into the main Earth Prime. This retroactively had made Superman one of the most experienced superheroes on Earth Prime now. In addition, the DEO now operates in the same space as ARGUS, which may lead to some conflict.
Probably the best part of all of this is that the space-faring nature of Supergirl now completes the Arrowverse slate and it now allows for easier crossovers (especially since Kara and Kate get along so well!)