If you are not old enough, you might not realize there is a Batman v Superman story line out there. In The Dark Knight Returns, we got to see a street fight between the two and it would be safe to say that this movie is going to play on that a little bit as well. The public is going to have to choose which type of superhero they want.
Right now, the only information that is very general and misleading is this “new threat”. There has not been any indication as to what that is, or who it could be for that matter. Fans are going to start speculating at some point and in the meantime, the studio, director, producer and cast is going to stay quiet on the matter.
Batman v Superman: Dawn of Justice is not going to be the only movie on the table for Snyder and the cast either. According to reports, there is plenty of superhero movies to make and that includes the second Batman v Superman: Dawn of Justice movie already in the works.