You either horribly date the character if you do, or you’re forced to use cheap and increasingly silly means to keep them relevant or in some cases still alive in the modern day. Captain America is one of the few characters that have managed to pull this off in an interesting way. With others it becomes increasingly silly overtime(Disco Dazzler) or increasingly convoluted overtime (when they use clones or time travel for example). The best characters are the ones whose origins are times less, and can be moved from one decade to another with only superficial changes.