Process support for knowledge work is far from being mastered in existing information systems. Predominant work ow management solutions are too rigid and provide no means to deal with unpredictable situations. Various case management approaches have been proposed to support this exibility for unstructured processes. Recently the Object Management Group published the Case Management Model and Notation (CMMN) as a standard notation for case management. In this paper we compare prominent de nitions of case management over the last twenty-three years against characteristics of knowledge-intensive processes (KiPs). Our goal is to evaluate the applicability of case management and CMMN for KiPs. We provide requirements for execution environments implementing CMMN and delineate existing case management approaches to advance the understanding of this important domain. We concluded that CMMN seems to be a suitable approach to KiPs when combined with an appropriate execution environment.