Spider-Man had a key role in Captain America: Civil War. But he wasn't present in any posters or film pics or trailers released by Marvel. Can anybody tell the reason?
Marvel did not have full unadulterated control over Spider-Man. Spider-Man is still under Sony control, so Sony would have major veto power over any instance of Spidey in marketing. To avoid any issue, and to inflate the "special guest star" factor for him, they avoided using him in all (meaning every piece of) marketing.