PinkRebel posted on their Instagram account with a logo and their first post!
They have teased that their concept is either going to be cute or girl crush and want fans to guess.
Guessing that they're girl crush because their username is @pinkrebel_crushi
They've also posted a video named "PinkRebel 핑크레벨 - Cute or Crush? Concept 티저" on their YouTube channel. The video doesn't really give a guess to their concept because it has a cake which is sweet and cute, but also has black and gold frosting which can be seen as a representation of cool/crush. It also has Beyonce's Flawless as the BGM which can be seen as girl crush.
Determine for yourself.
And follow PinkRebel on Instagram.