CXCL9 and melanoma: Correspondingly, the concentrations of CXCL9 and αPD-L1 proteins in the culture supernatants of NPTyr-C9AP-transfected B16-F10 cells reached 0.47 and 2.19 ng ml−1, which were much higher than that of other cells due to the melanoma specificity of NPTyr-C9AP (Fig. 2h).