Avengers: Infinity War - Predicting All 67 Characters
25. Spider-Man
By the time Infinity War rolls around, the incredible deal between Marvel and Sony will have already seen Tom Holland star in two MCU movies as Peter Parker, making an appearance in Infinity War a no brainer. And, given the Russo's (incidentally the directors who introduced him) will have had time to plan his inclusion, it's likely to be a bigger role than the inevitable extended cameo in Civil War.
24-22. Mary Jane, Aunt May And J. Jonah Jameson
One thing Sony will be very keen for Marvel to do is not just legitimise their new Spider-Man, but also his wider world. That's why Marisa Tomei's Aunt May is rumoured for Civil War and also why it's probable some of Holland's supporting cast will appear in later Marvel movies. The best bets are Aunt May and Mary Jane (or Gwen Stacey, depending what love interest we wind up getting), although don't rule out a cheeky J. Jonah Jameson cameo too.