On January 16, Mnet released a preview for the group's new reality show, "This is INFINITE", and on February 6, the show aired its first broadcast This was their first variety show as a group since Ranking King.
After performing in 15 countries for their world tour, "One Great Step", Infinite held an encore concert titled "One Great Step Returns" to wrap up their world tour. The encore concert was held for 2 days on February 28 and March 1 at Olympic Gymnastics Arena in Seoul. During the concert, a new sub unit, Infinite F, was announced which consists of members Sungyeol, Sungjong, and L. Infinite F performed a new song, "Heart Is Beating" (translated title from Korean) while their other sub unit, Infinite H, also performed a new song titled "Alone" and "When I Close My Eyes", a self-composed, written solo track performed by Woohyun. The group also announced that they will be making a comeback in April during the concert.
On February 20th broadcast of "This is INFINITE", a short prologue video was shown featuring Woohyun and Shinee's Key, introducing a new sub unit, Toheart. The sub unit made their debut on March 10.