The infamous redshirts -- doomed to die solely because of their uniform color -- have long been an indescribably essential part of Star Trek culture. What started as a joke turned into a celebration to the point where an entire series -- Star Trek: Lower Decks -- centers around them. The concept isn't going anywhere, and by now, red shirts become a part of the fun.
Source:https://www.cbr.com/red-shirt-meaning/