CD274 and melanoma: As shown in Fig. 1a, the PD-(L)1 monotherapy validation cohort (n = 248; PD-1 n = 194 [78%] and n = 54 [22%] PD-L1) was comprised of patients with 24 tumor types (25% melanoma [most frequent tumor type]); tumor types and demographics are provided in Supplementary Data 2 and 3.