Case Management - How is it categorized? Service? Help Desk? Other?

Hi all, just wondering. Working specifically with Cases, it seems that it falls between the cracks with documentation. Even here in the forums there isn't a specific "Case Management" topic, and in the various online documentation it isn't always clear where we are supposed to look.

Is Case Management implicitly tied to Help Desk? Always? (i.e. What's New has Case Management under Help Desk). When in doubt is it an ISR? Or is there a separate stripe/stream for Cases?