Marvel and Sony have made a deal to bring Spider-Man to the Marvel Cinematic Universe. Sony will still finance, produce and release the films with Marvel’s Kevin Feige producing. Spidey will first appear in a Marvel movie before getting a new film set for July 18, 2017.
This works out for both parties involved. Sony keeps Spider-Man and gets the push of having him be involved in the MCU that can shit gold. Marvel gets to use its most recognizable character in future Marvel movies, helping Disney further towards their plans of becoming a world-controlling shadow corporation.
My guess is that Spider-Man will appear in Captain America: Civil War because, read a comic. He will be (likely) recast so start your wagers now. If we do get a new Spidey, I do feel for Andrew Garfield who was a great Peter Parker, even though his second movie failed him. He is a lifelong fan and it showed.
To welcome the web-slinger back, Marvel has shifted dates to make room.
Thor: Ragnarok goes from July 28, 2017 to November 3, 2017.
Black Panther goes from November 3, 2017 to July 6, 2018.
Captain Marvel goes from July 6, 2018 to November 2, 2018.
Inhumans goes from November 2, 2018 to July 12, 2019.
On a side note: I would be perfectly fine having Alfred Molina return as Doctor Octopus.