Marvel securing the rights to use Spider-Man in the Marvel Cinematic Universe was a minor triumph for the company, and before it happened, Captain America: Civil War would’ve been a little different.
As revealed by Christopher Markus and Stephen McFeely, the screenwriters for Captain America: Civil War, during a recent appearance on the Fatman on Batman podcast, there were plans underway for the film before Spider-Man showed up. Before the rights to the hero were secured, his place in the narrative was taken by another hero instead (thanks to Screen Rant for the transcription):
McFeely: [Tony Stark] would recruit somebody else. He probably recruits Ant-Man, I think would be that idea. Well, we had a section where you could recruit somebody, right?
Markus, “[Tony] actually went to San Francisco. It would not have been as cool.
McFeely “I believe [Scott] was watching his daughter play soccer. It wasn’t very good.
In the movie as it was finally written, Ant-Man sides with Captain America, while Tony Stark recruits Spider-Man to fight on his side against the illegal heroes. And, the writers are correct: the original idea was not nearly as good.