In another report, increasing expression levels of PD-L1 in TAMs, 2 months after the administration of anti-PD-1 Abs in patients with advanced melanoma, was correlated with the response to immunotherapy (53), suggesting that PD-L1 expression in TAMs could be a biomarker that predicts the effectiveness of anti-PD-1 Ab therapy. Here, CD274 is linked to melanoma.