Human and software agents are more and more often interacting in groups in which directives are originated as well as addressed by humans or software agents. Among challenges raised by the rise of such heterogeneous groups, referred to as Human-Agent Collectives (HACs), resilience and robustness remain an open question. In this paper, the factors that influence the resilience and robustness of HACs are identified based on former research concerning interdependent and complex networks. The two main factors identified in the paper are (1) interactions between HACs with their open-networked environment, (2) the structure of the interactions among members of the HACs.