Dong Si Cheng (董思成), better known by his stage name WINWIN (윈윈), is a Chinese singer and dancer. He is a member of the boy group NCT and its units NCT 127 and WayV.
He was born on October 28, 1997 in Zhejiang, China.
In January 2016, he was introduced as part of SM's pre-debut training team SMROOKIES. Before his debut, he was featured in the music video of NCT U's "WITHOUT YOU". In July, WINWIN officially debuted as a member of NCT, in the unit NCT 127, with the mini album NCT #127.
In January 2019, he debuted in the chinese unit WayV with the EP The Vision.