In a 2017 episode of The Hollywood Reporter’s Awards Chatter podcast, Ryan Reynolds revealed that just before he agreed to Green Lantern, he called Fox one final time to see if there was any hope of a Deadpool film being made.
…I think I might actually get this (Green Lantern) so I quickly called the executive I knew at Fox who had Deadpool and I said look, I am standing at the altar right now, about to say I do to someone else. I will walk away from this if you even think you’ll make a Deadpool movie. If you can make a Deadpool movie with me. And he said ‘unfortunately no, I don’t think that’s going to happen.’ So I went off and did Green Lantern.
Reynolds went on to say that he began writing Deadpool whilst filming Green Lantern:
Writers Rhett Reese and Paul Wernick flew to New Orleans in 2008 or 2009. While I was shooting Green Lantern we were all together writing Deadpool in the hopes that somehow, someway it would come back to life. We were breaking the story of the original Deadpool movie in a house that was being paid for by Green Lantern’s dime.
After 10 years in purgatory, Deadpool made it onto the big screen in 2016 and was one of the biggest successes that year, bringing in a box office of $783.1m on a budget of $58m.