Superman may no longer be comics' biggest character, but he's definitely still their biggest icon. Without Superman, the world of serialized superhero comics might not exist. His success in the Golden Age opened the floodgates for heroes and dark antiheroes alike and since his debut, he's starred in almost as many titles as any other character. Superman has been around for over eighty years and had plenty of time to accumulate a lot of starring roles in comics.
Source:https://www.cbr.com/best-first-issues-superman-dc-comics/