Chicago has been active since the mid 60s and has since garnered wide spread fame among both rock and jazz enthusiasts. Because of their unique style and genre, Chicago has been able to draw from the fan-bases of multiple bands and genres. The band has released dozens of albums, usually with a classic rock feel much like queen but with a distinctly jazz flavor. Notably, all of the bands albums are self-titled followed by an appropriate roman numeral which labels what number the album is. There are only a few exceptions to this and their most current release of new material is 'Chicago XXX' which came out in 2006.
The band predominately spends its time touring because of the wide demand to see them and the large catalog of music they already have released. Catching them on tour oftentimes won't be difficult because of their frequent tours, however getting a good seat may be near impossible.
Unlike most bands, Chicago has an almost legendary history and has more fans than they do seats in the arenas that they play. If you're planning to see Chicago, make sure to call in early to get the first selection on tickets.