New Marvel Mystery Movie In The Works?

While Stan Lee has been dropping hints of Black Panther, Doctor Strange, and Inhumans being upcoming movies for Marvel Studios, a source is telling us that "Things are in flux. There's a new movie in play." We've been unable to get any answers on exactly what this potential new Marvel Studios movie is. For all we know, it could be the Inhumans movie that Stan Lee said was probable or it could be another stab at a standalone Hulk movie or a sequel to Guardians Of The Galaxy, but there is definitely something afoot at Marvel Studios that could add a twist to their existing plans. Could it have something to do with whatever Vin Diesel teased as a merging of the brands? Vin Diesel has indicated that Marvel Studios originally contacted him about playing a new property in 2016, so it would certainly line up with the rumors we hear of some mystery new Marvel movie having the Marvel Studios executives really excited. What do you think this mystery movie could be?