Increased circulating CXCL9 and CXCL10 have been detected in patients with irAEs when tested 2 weeks and 6 weeks post anti-PD-1, PD-L1, or CTLA-4 treatment.261 From the above research process, it can be seen that different biomarkers vary with cancer type and checkpoint target. This evidence concerns the gene PDCD1 and cancer.