Additionally, although we developed and validated the IRS model across patients treated with multiple PD-(L)1 monotherapies and tumor types, not all solid tumor types were represented in these analyses and prospective studies could determine if more optimized thresholds (or further stratification beyond two IRS groups) may improve performance in specific tumor types or better predict PD-1 vs. PD-L1 therapy benefit. Here, PDCD1 is linked to neoplasm.