Avengers: Infinity War picked up where Captain America: Civil War had left off, and one Steve Rogers line makes his fight against Iron Man more tragic. While there were still two years of solo MCU movies between Civil War and Infinity War, the latter is when the consequences of the dissolution of the Avengers were truly felt. Thanos was heading to Earth to finish collecting the Infinity Stones, yet the world’s most powerful force, the only thing that could stand a chance against the Mad Titan, had been split up.
The first act of Infinity War proved that the aftermath of Civil War had real consequences for the story. For example, Wanda and Vision were away without communicating with Iron Man, and the rest of the Avengers, Hawkeye and Ant-Man had accepted deals to stay out of the superhero game, and Captain America, Falcon, and Black Widow had to spend the next couple of years as fugitives. By the time Bruce Banner fell into Doctor Strange’s Sanctum Sanctorum with the news of Thanos’ attack, there was no way for the Avengers to act quickly.
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Earth’s first response against Thanos’ Black Order came with Iron Man, Doctor Strange, and Spider-Man aboard the enemy's ship. The disappearance of Iron Man led to one very noticeable Captain America line, in which Rogers says that “(...) Earth has just lost its best defender.” Obviously, that line referred to Iron Man, who at the time could be dead as far as the people on Earth knew. This was the first time Steve Rogers acknowledged Tony Stark’s importance to the world in such a significant way, and it ironically came after their Civil War fight. Steve Rogers and Tony Stark were never on the same page
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