Answer
Whatcha Doin is a collaboration between Chungha and Yesung, released in 2018. The song is a mid-tempo R&B track with a catchy melody and lyrics that explore the feelings of longing and desire in a relationship. The song was a commercial success, peaking at number two on the South Korean Gaon Digital Chart and winning several awards, including the Digital Song of the Year at the Mnet Asian Music Awards.