CBS is following the trend with a series commitment to Supergirl, by the creators of Arrow and FlashVariety is reporting.
The Warner Bros. Television series was already in development by Flash and Arrow co-creators Berlanti and Adler (see "'Flash' Producers Confirm 'Supergirl' Rumors, Hint at Wally West"), and this move confirms that all major networks will have live-action comic book-based series on the air or in development: the CW has Arrow and Flash, NBC has Constantine (see "'Constantine' TV Series Adds Jim Corrigan"), Fox has Gotham (see "Netflix Snatches 'Gotham' Streaming Rights") and a recent put pilot order for Lucifer (see "'Lucifer' Headed to TV"),  and ABC has Marvel’s Agents of S.H.I.E.L.D and its upcoming spinoff Agent Carter (see "'Agent Carter' Directors Deja Vu").
According to Variety, the plot will be based on the story of Kara Zor-El, Superman’s cousin who also escaped Krypton’s destruction.  She has kept her abilities a secret since landing on Earth, but at the age of 24, decides to embrace her superhuman powers and become a hero.