One of the reasons fans have been so astounded by Marvel's reluctance for a Black Widow film is Scarlett Johansson's obvious box office viability. If there was any doubt about that, all one needed to do was look at last year's $450M haul for Lucy, which otherwise is just another of Luc Besson's stable of generic action flicks. It was a film that came out of nowhere to be a smash, and despite an ending that makes a follow-up seem unlikely, it appears a sequel is indeed on the way.
Besson's production company EuropaCorp announced at CineEurope 2015 their entire upcoming slate of projects, and in development are Lucy 2 and perhaps more surprisingly, a sequel to Zoe Saldana's Colombiana which opened in 2011 and only earned about $60M worldwide.
Lucy had Johansson as a woman who ingests a mysterious drug that causes her to use her brain at maximum capability, giving her incredible telepathic and telekinetic abilities. It'll be interesting to see how they get around what happens to the title character, though, and if they plan to bring Johansson back. Any sequels would be far less marketable without her in the starring role. Colombiana starred Saldana as a female assassin who sets out to kill the man who murdered her family. The film was largely forgettable and there's no direct need for a sequel to follow the same character.
Besson isn't opposed to replacing the stars of his various franchises. This summer's Transporter Refueled will be the first not to feature Jason Statham.
Since Besson is in such a mood, how about a sequel to Lockout with Guy Pearce? [Allocine]