1. Howard Stark: In the film, Howard Stark, the father of Tony Stark (Iron Man), plays a significant role. This serves as a connection to the larger Marvel Cinematic Universe (MCU). 2. The Tesseract: The Tesseract, a powerful cosmic artifact, is a central plot point in the movie. This object has appeared in several other MCU films, including "Thor" and "The Avengers." 3. The Howling Commandos: Captain America's team, the Howling Commandos, includes characters such as Dum Dum Dugan and Gabe Jones. These characters have their origins in the Marvel Comics and have made appearances in various comic book series. 4. Stark Expo: In a scene set in 1943, there is a billboard for the Stark Expo. This is a reference to the World's Fair held by Howard Stark, which is also featured in "Iron Man 2." 5. Red Skull's Background: When Red Skull first appears without his mask, he is wearing a black uniform with an SS symbol. This symbolizes his previous affi