The initial idea for Wayward Sisters came from the shows huge fan base. Disappointed after a previous attempt at a Supernatural spin-off called Bloodlines, fans expressed their desire for an all female series called Wayward Daughters. The idea amassed a huge following on social media and even gained support from the cast of Supernatural. The writers listened, albeit 3 years later and the result is Wayward Sisters.
When Jody calls Claire to tell her Sam and Dean are missing, Jody says, "They were on a hunting trip, and I haven't heard from them for a few days." This mirrors the series pilot. When Dean went to get Sam in that episode, Dean said, "Dad went on a hunting trip, and he hasn't been home in a few days."
The CW announced this will be a backdoor pilot set to air as Supernatural's first episode of 2018. The Supernatural spinoff is slated to be named Wayward Sisters, an adaption of the Supernatural theme song Wayward Son by Kansas.
The (potential) spin-off of Supernatural revolving around Sheriff turned Hunter Jody Mills (Kim Rhodes), Alex Jones (Katherine Ramdeen) ex-vampire food bait, and Claire Novak (Kathryn Newton), Jimmy Novak's (Castiel's vessel) daughter turned Hunter. Also bringing together Donna Hanscum (Briana Buckmaster), another Sheriff turned hunter, and Patience Turner (Clark Backo), the granddaughter of Missouri Moseley (Loretta Devine), who finds her psychic abilities are developing following her grandmother's passing. The episode will serve as a backdoor pilot.
As of May 2018, the CW network had canceled/not picked up Wayward Sisters. CW President was quoted as saying of the show and its characters/actors. "We hope they continue on as guest stars on Supernatural... But we did not feel creatively that the show was where we wanted it to be..."