After a bunch of rumors arising from the Sony hacks, Marvel finally confirmed that Spider-Man will be making an appearance in the Marvel Cinematic Universe:
Under the deal, the new Spider-Man will first appear in a Marvel film from Marvel's Cinematic Universe (MCU). Sony Pictures will thereafter release the next installment of its $4 billion Spider-Man franchise, on July 28, 2017, in a film that will be co-produced by Kevin Feige and his expert team at Marvel and Amy Pascal, who oversaw the franchise launch for the studio 13 years ago. Together, they will collaborate on a new creative direction for the web slinger. Sony Pictures will continue to finance, distribute, own and have final creative control of the Spider-Man films.
So for at least a brief time Marvel and Sony will make like two pizzas slapping together and bring the ol' Webhead to a Marvel movie. Since the next solo Spider-Man movie is set for July 28, 2017 and Spider-Man's appearance in a Marvel movie is before that, there are only a few possibilities for that movie appearance (namely Captain America: Civil War, Doctor Strange, or Guardians of the Galaxy 2).*
Now that Spider-Man is "official" with Marvel now, they have shifted the release dates for several other Marvel titles on the board: Thor: Ragnarok has been moved to Nov. 3, 2017 (from its July 28, 2017 date). Black Panther will now open July 6, 2018 (from its old date of Nov. 3, 2017). Captain Marvel moved to Nov. 2, 2018 (from July 6, 2018), and Inhumans is slotted for July 12, 2019 (from its original Nov. 2, 2018 date).
That may not be the only Spider-Man appearance in a Marvel film, as:
Marvel and Sony Pictures are also exploring opportunities to integrate characters from the MCU into future Spider-Man films
Of course all involved in the announcement were thrilled and happy.
*Since the article was orginally written, the release dates of several movies were changed, this article was updated to reflect that. Thanks Jeremy Shane.