Abstract
Programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) interaction protects cancer cells from immune destruction. Blocking the pathway allows infiltrated T cells to kill tumor cells (TCs), in order to prevent tumor proliferation and distant migration. Immunotherapy with checkpoint blockade (CPB) has emerged as a powerful weapon conquering multiple cancer. However, PD-L1 expression and tumor mutation burden (TMB) are not perfect biomarkers for patients selection to treated with immunotherapy. Increasing evidence showed that other immune-related factored must be payed enough attention and combined biomarkers present promising prospects. Here, we give an overview on available biomarkers in clinic and potential biomarkers for future research.