Marvel Studios' Kevin Feige recently gave an update regarding the possibility of a "Black Widow" spin-off feature starring Scarlett Johansson reprising her role as former Soviet superspy 'Natasha Romanoff' :
"Her part in 'Avengers: Age Of Ultron' is very, very big and further develops her character, " said Feige.
"The plans we have for her through the rest of the 'Avengers' saga...
"...are very big and she is a linchpin, in fact, to those films.
"So instead of taking her out there or doing a prequel which we haven’t done yet...
"...we’re continuing the forward momentum of the continuity of the 'Cinematic Universe'...
"...of which 'Widow' is a key part."