PDCD1LG2 and melanoma: Taube et al have reported that tumor and APCs can both express PD-L2 in patients with advanced, treatment-refractory solid tumors including NSCLC, melanoma, kidney, castration-resistant prostate cancer) and CRC.39 They assessed PD-L2 expression in 38 tumor specimens and found that PD-L2 was less frequently expressed than PD-L1 and was almost geographically associated with PD-L1 expression.