This comes from Latino Review (so take it with a huge, boulder sized grain of salt), but there’s a chance Spider-Man might be in Avengers: Infinity War Part 1.
If what Latino Review says is accurate then the article linked above is fairly spoiler heavy – but that’s the big, important bit. The author claims that Sony and Marvel have come to a deal, and that while it’s too late to integrate Spidey into Civil War, the third Avengers film is the perfect spot for him.
Of course, Latino Review doesn’t exactly cite their sources on this one, so it could all be a giant pile of Malarky.
But even a broken clock is right twice a day.
Via Latino Review