Computer-Assisted Medical Intervention systems aim at providing assistance to clinicians for planning, simulating and executing safely, accurately and efficiently diagnostic or therapeutic actions. Such systems are based on a strong connection between digital data (patient images and signals, a priori information embedded in atlases, statistical models, biomechanical models, surgical protocols, etc.) and the real world where the clinician has to operate the patient. Collections of sensors may enable intra-operative data acquisition for refined decision making and action monitoring; actuators such as robots may be involved in the action itself with different levels of cooperation with a human operator. CAMI systems raise typical issues of CPS related to autonomy, security or dependability. In order to illustrate how these issues can be tackled in real applications, we will introduce the domain of CAMI and we will describe several examples from clinical end-user specifications to scientific and technological solutions we implemented.