Conversation so far:
What is the Kozmic Blues band?
After splitting from Big Brother and the Holding Company, Janice Joplin formed a new backup group, the Kozmic Blues Band.
Was the Kozmic Blues band successful?
The Kozmic Blues was Janice Joplin's backup band.

Question: What did they sing?
Self-contained rewrite: What did the Kozmic Blues  sing?