The film features all of the group's members, including long-estranged former drummer Danny Seraphine. They discuss their lives and musical legacy. It's apparently not all positive. There's a YouTube clip linked on Chicago's website where the guys admit to making the kind of mistakes young musicians with too much money often make.
From their Chicago 17 album here's the group's #1 hit "You're The Inspiration" from iHeartRadio: