After much deliberation, its been announced that Supergirl has been renewed for Season 2, but it will air on The CW rather than CBS.
This might mean that Supergirl will move production from Los Angeles to Vancouver, though The CW wouldnt confirm that.
This move was finally confirmed by EW after weeks of reports about network executives contemplating bringing Supergirl to the same home as other DC superhero shows Arrow, The Flash and Legends of Tomorrow.
The report noted that when DVR playback was accounted for, Supergirl averaged around 9.8 million viewers, which is low by CBSs standards, but would be amazing for The CW.