The next film is Iron Man 2 and this one has a bit of history to go with it. In the past, Anton Vanko had worked with Tony’s father Howard Stark on the first arc reactor and was stealing research from Stark Industries and planning to sell the arc reactor for profit. He was deported back to Russia. Anton convinced his son, Ivan Vanko, to seek revenge for what should have been their legacy. Ivan Vanko creates a suit reminiscent of an amalgamation of the villains Crimson Dynamo and Whiplash, both of whom their alter egos were Anton Vanko in the comics but completely unrelated to one another. He serves as the main villain of the movie along with another famous Iron Man villain and business rival Justin Hammer, albeit he is much younger in the film and nowhere near as sinister. 

Rhodey takes up the mantle of War Machine. Natasha Romanoff aka the Black Widow joins the MCU initially as a secretary/assistant to Stark, taking Pepper’s former place after she becomes the new CEO of Stark Industries. After the end credits, the major connection to the next MCU puzzle piece is the scene showing Thor’s hammer Mjolnir being discovered in New Mexico.