Being the culmination of 10 years worth of stories, Avengers: Infinity War will undoubtedly be the MCU film that will require the most from audiences regarding familiarity with the films and characters. Whether it be of major significance or minute details, every film will tie-in to Infinity War one way or another. Speaking the several members of the press about how the Phase 3 films lead into Infinity War, the Russos revealed that Ant-Man & the Wasp will have some plot points that directly stem from Infinity War.
They all lead in in their own way, I think. As far as plot elements that actually drive towards the story, again, I think Marvel does a great job of segmenting the movies so that you can have your own experience in each film. I think from a plot standpoint, if there’s any corollary, Ant-Man 2 probably has some elements that stitch in.
One unusual thing about the Phase 3 films is that none of them set up Avengers: Infinity War the same way Thor and Captain America: The First Avengers led into the first Avengers film. In Thor and Captain America, you not only get a taste of the villain for Avengers but you also get familiarized with the Tesseract, two major components of Marvel’s first superhero team-up film. For Phase 3, the films have been mostly independent of Thanos’ quest for the stones. Sure, we see Thanos’ ship at the end of Thor: Ragnarok but that tie-in feels like an afterthought at most.
Sandwiched between two Avenger films, the trailer for Ant-Man & the Wasp makes it seem like its a totally independent story with Scott and crew running away from the government. Having Ant-Man & the Wasp, a film whose lead is under house arrest, be the Phase 3 film with the most discernible connection to an epic space saga is both ironic and awesome. I’m dying to know what this connection will be. Either both films take place simultaneously (Ant-Man & the Wasp could be a prequel of sorts where Scott sees what happens in New York) or that the Quantum Realm will play a part in Avengers: Infinity War.