Therefore, BATF2 can be a potential biomarker to evaluate the efficacy of ICBs, low BATF2 expression indicating higher expression of PD-L1, and tracking dynamic BATF2 expression level from plasma may serve as an indicator for PD-L1 expression in tumor instead of multiple repeats of sample biopsies from patients (Fig. 5). The gene discussed is BATF2; the disease is neoplasm.