As far as Maslansky is concerned, though, the civilian attire preferred by Luke Cage, Jessica Jones, and for the time being, anyway, Danny Rand, is specific enough that it becomes their costumes.
Costume designer Stephanie Maslansky talks how Marvel’s The Defenders turn civilian clothes into their superhero costumes.
I think The Defenders will be full of surprises and it will be exciting to see how these characters evolve.”
In other words, with the exception of one person, The Defenders don’t dress like your traditional superhero.