IOI's "4th anniversary debut" ad is Hot Topic. .
● Debut on May 4, 2016 ● Although we were active until January 31, 2017, we will reassemble in 2021 and promise to hold a concert ● Fans waiting for that day will have a commemorative advertisement for their fourth debut this year Implementation. "Congratulations on the 4th anniversary" "I want to see you IOI" "Is it the 4th anniversary?" "It's only one year left".