Nayoung

In June 2018, Kim Nayoung participated in Mnet's survival show Produce 48 as a contestant under Banana Culture, but was eliminated in the eleventh episode after achieving 21st place. Later that year, she was announced as a member of the pre-debut trainee group, Banana Culture Newkid. However, by spring 2019, the group's debut had been cancelled.

On April 21, 2021, Nayoung was revealed as a member of Cube Entertainment's girl group, LIGHTSUM. The group debuted on June 10 with their first single "Vanilla".