The Marvel Cinematic Universe has brought Marvel's characters to the general public in a way no one thought possible. Marvel characters have become household names and despite some recent failures at the box office, it's still the biggest entertainment franchise ever. The centerpiece of the MCU has always been the Avengers films. These movies are the equivalent of event comics, the massive crossovers that bring together the greatest number of heroes to fight the most dangerous foes. These movies have served as the culmination of the stories set up in the other MCU movies and have a reputation for being the best. These Avengers movies may combine a huge amount of characters, but there's a core to each one - Captain America, Iron Man, Thor, Hawkeye, Black Widow, and the Hulk.
Source:https://www.cbr.com/every-avengers-movie-hulk-chronological/