CD274 and melanoma: Expression of PD-L1 and PD-1 were the earliest recognized candidate biomarkers used to predict the efficacy of immunotherapy (Topalian et al., 2012; Taube et al., 2014; Doroshow et al., 2021), and were approved by the FDA for pre-treatment evaluation in patients with melanoma (Kaushik et al., 2022), bladder cancer (Roviello et al., 2021), gastric cancer (Huynh et al., 2021), and cervical cancer (Odiase et al., 2021).