In December 2015, Cube Entertainment announced that they were preparing to debut a boy group in mid-2016, 4 years after BtoB's debut. On April 26, 2016, Cube revealed its new boy group, Pentagon, with the group trailer "Come into the World."
The final lineup of Pentagon was decided through Mnet's reality program, Pentagon Maker. Pentagon Maker aired online through Mnet's digital content brand, M2, and showcased the members challenging five aspects: Performance, Dance, Teamwork, Talent and Mind.