The release of Avengers: Endgame was really the end of an era for Marvel. Many of the characters had finished their stories and no longer had a role to play in the MCU, such as Captain America and Iron Man. Going into Phase 4, a lot of characters have been expanded upon or given new life, while in other cases, brand new characters and stories have been introduced. Most notably, the tone of Phase 4 feels different, and it distinguishes this era of Marvel from the previous ones.