James Gunn has shared information about Supergirl, potentially tying into a larger DC Universe story that may involve other characters, including Superman and possibly Lex Luthor. The details of Supergirl's role and how it connects to other DC projects are not entirely clear, with some outlets suggesting a significant part in an upcoming movie and others noting potential plot inconsistencies. The comments from Gunn also mention other DC characters and projects, including Wonder Woman, but the specifics of these plans are not well defined.