MXM is a duo group under Brand New Music that consists of Brand New Boys members Lim Youngmin and Kim Donghyun.
Lim Youngmin and Kim Donghyun met as trainees under Brand New Music. They represented the agency alongside Lee Daehwi and Park Woojin in "Produce 101." When the show ended, neither of the two earned a spot in the project unit Wanna One. Youngmin finished 15th overall, while Donghyun was eliminated before the finale took place.
On July 12, it was announced that Youngmin and Donghyun would debut as a project unit. Both had signed exclusive contracts with Brand New Music before "Produce 101" and becoming members of Brand New Boys. The unit is called MXM, which reportedly stands for both "Mix and Match" and "More x More." The former refers to the duo’s compatibility as a group despite contrasting qualities, while the latter refers to their determination to develop as a duo. On July 27, they released a two-track promotional single titled "Good Day." Donghyun wrote the lyrics of the single's second track "I Just Do" with Youngmin, as well as arranging and producing it with Brand New Music producer Kiggen.
MXM officially debuted on September 6 with the release of their first mini album, Unmix. The album contains seven tracks, including "Good Day" and "I Just Do." The track "I'm the One" was written and produced by Brand New Music producers 9999 and Esbee.
On September 22, the duo participated in Brand New Music’s annual concert titled “Brand New World Seoul,” held at the Seoul Jangchung Arena.