I’m going to say for the record that this is strictly a rumor at this point. As reported by Latino Review, a deal has went through with Sony and Marvel. This was initially hinted at with the big Sony Hack It’s too late for Spidey to show up in Civil War other than a post-credits seen, but all signs points to May 4th, 2018 – Avengers: Infinity Wars Part 1.
I have some doubts about this because why would Sony give up one of their prized properties? I know the Amazing Spider-Man part 2 suffered from a very loaded movie, but is it salvageable? Is Andrew Garfield going to return as Spider-Man? Then again, as we go through the phases, there are hints of our movie Avengers changing. The report from Latino Report discusses those possibilities as well. Wouldn’t Marvel want to reveal this grandiose scheme at I don’t know…Comic-Con? Looks like Spider-Man is going to fill that void. Or will he?