Every so often, in the decade following The Comeback’s second-season finale in December 2014, co-creators Lisa Kudrow and Michael Patrick King would huddle to brainstorm ways to resuscitate Valerie Cherish. They weren’t ready to let a fame-obsessed, red-headed fan favorite flatline to has-been status. HBO executives had left the door open for a third, but the time between them was ticking toward unprecedented. But pop culture had never buried Cherish either. From its 2005 debut, The Comeback overcame low ratings to become a cult hit, beloved for its razor-sharp satire of Hollywood and commentary on the changing nature of celebrity. Audiences grew slowly but surely over the years, pulled in by an attraction to Kudrow’s creation: a washed-up TV actress who swims upstream to reclaim a semblance of her former glory amid a sea of brighter, younger things.…