Chinese Academy of Sciences Mar 9 2026 Immune checkpoint inhibitors targeting PD-1 and PD-L1 have revolutionized cancer therapy, delivering long-term survival benefits in several malignancies. However, nearly half of patients show limited response or develop resistance, while some discontinue treatment due to immune-related side effects. Traditional biomarkers, including PD-L1 expression and tumor mutation burden, fail to fully explain this variability. Increasing evidence suggests that