Captain America: Civil War is only a month away, and with it the official debut of the new Marvel Cinematic Universe version of Spider-Man: a supporting turn designed to establish that the new Peter Parker exists as part of the Marvel Cinematic Universe, as well as to win back audiences who may be feeling burnt out on the wall-crawler after the release of Spider-Man 3 and the Amazing Spider-Man reboot film series - a task that may be easier said than done.
Of course, now that Spidey (as played by Tom Holland) can help out his fellow Marvel superheroes in Civil War, there's no reason they can't return favor in future MCU films. According to Marvel Studios President of Production Kevin Feige, that might be exactly the plan starting with the 2017 Spider-Man solo film/MCU reboot.
Speaking to EW as part of ongoing promotions for the hotly-anticipated third Captain America movie, Feige didn't shy away from questions about whether or not big-name Marvel character cameos are in the cards for the as-yet officially untitled Spider-Man MCU solo feature - which is being produced and released by Sony but overseen by Marvel. Said Feige:
"He is in the universe now, and the fun of the universe is that characters go back and forth.”
However, exactly which established MCU characters may appear in Holland's solo Spider-Man film is unknown. Early rumors about the solo feature had suggested a significant role for Robert Downey Jr's Tony Stark, but most talk of immediate-future endeavors for any of the core Avengers has gone mum in recent months - likely to avoid spoiling which heroes make it out of Civil War intact. While Spider-Man's traditional setup often keeps the character and his supporting cast on the fringes of bigger, more powerful heroes' business, a younger Spider-Man who is already involved in something like Civil War's superhero-registration clash would likely have more connections going forward.
Whereas Phase 1 MCU films kept the individual Avengers largely dealing with their own issues and supporting-cast in their solo features, the studio has become more loose about crossovers in both the MCU's Phase 2 and especially the fast-approaching Phase 3. Along with Civil War's bevy of supporting players, The Falcon showed up in Ant-Man while Thor's third outing, Ragnarok, is a team-up vehicle featuring the God of Thunder and The Incredible Hulk. So the door for various heroes (or villains) to make their presence known in Spider-Man would seem to be decidedly wide open; especially with actors like Downey signing up for longer contracts and Chris Evans (Captain America) - who once seemed all but dead-set on putting down his shield after Avengers: Infinity War - indicating he might be willing to stick around, after all.
One extremely outside possibility might be for Spider-Man to be the place where Marvel's often at-odds TV and streaming ventures could tip over into the movies. Unlike the more global (or intergalactic) sweep of the other Marvel franchises, the new Spider-Man is expected to be a smaller-scale story grounded in teenaged Peter Parker's life in New York City - placing him geographically-adjacent to the events of Daredevil and Jessica Jones. While it's unlikely any of those main characters could turn up to say hello, it may end up being noteworthy that Daredevil nemesis The Kingpin (currently getting a big push in the comics, incidentally) was originally an enemy of Spider-Man.
Perhaps the most unlikely candidates to appear, however, were teased by Civil War co-director Joe Russo, who offered "Let’s just say … Great Lakes Avengers" in the same EW interview. A comedy-focused team of Marvel also-rans who debuted in the late-1980s when the Avengers had themselves split into complimentary East and West Coast factions, the team is known as a rallying-point for offbeat characters like Squirrel Girl and Dinah Soar - none of whom have been mentioned for movie plans any time soon.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange– November 4, 2016; Guardians of the Galaxy 2 – May 5, 2017; Spider-Man – July 7, 2017; Thor: Ragnarok – November 3, 2017; Black Panther – February 16, 2018; The Avengers: Infinity War Part 1 – May 4, 2018; Ant-Man and the Wasp – July 6, 2018; Captain Marvel – March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.