Business process modeling is essential for organizations to comprehend, analyze, and enhance their business operations. The business process model and notation (BPMN) is a standard widely adopted for illustrating business processes. However, it falls short when modeling roles, interactions, and responsibilities within complex modern processes that involve digital, human, and non-human entities, typically found in cyber-physical systems (CPS). In this paper, we introduce Role-based BPMN (RBPMN), a standard-compliant extension of BPMN 2.0 that distinctly depicts roles and their interactions within business processes. We underscore the value of RBPMN and a role-based context modeling approach through a modeling example in CPS that facilitates the representation of role-based variations in the process flow, namely a production process in a smart factory. Our findings suggest that RBPMN is a valuable BPMN extension that enhances the expressiveness, variability, and comprehensiveness of business process models, especially in complex and context-sensitive processes.