Earlier this year, “Supergirl” was benched while “DC’s Legends of Tomorrow” took over the Monday night time slot with The CW president Mark Pedowitz explaining at the Television Critics Association winter press tour that The CW was worried about an “overload” if they aired more than four DC Superhero TV shows in any given week. With “The Flash”, “Arrow” and the new series “Black Lightning” being of higher priority, the network decided to inter-change between “Supergirl” and “Legends” on Monday nights.
Back in February “Supergirl” took an unprecedented nine-week hiatus, with “DC’s Legends of Tomorrow” occupying the Monday time slot until April 9, at which point “Supergirl” will return with new episodes on April 16 and run continuously right through to Monday, June 18 when the Season 3 finale will air.
The reason no “Supergirl” Season 4 announcement has been forthcoming is due to the fact that The CW is set to announce that “Supergirl” and “DC’s Legends of Tomorrow” will merge into one show titled “Supergirl and the Legends”.
It’s unclear how the dynamic of the show will work, but it’s understood that Kara will take on a dual leadership role of the Legends alongside Sara Lance as the Legends head back in time to Krypton to explore what happened to her home planet just before it exploded.