Chronic TCR stimulation and PD-1 expression triggerT cell dysfunctionality, and cancer cells manipulate the PD-1 pathwayto escape and resist immune responses.10,21 Here, we offera TME modeling and cell–cell interaction to deepen our understandingof cell behavior in a TME via 3D culture in a lung TME chip. The gene discussed is PDCD1; the disease is cancer.