Results from large, randomized Phase 3 trials including patients with unresectable Stage III or Stage IV metastatic melanoma revealed that patients treated with anti-PD-1 ± anti-CTLA-4 had better response rates, PFS and OS, compared to those treated with ipilimumab alone, regardless of PD-L1 expression, indicating that tumor PD-L1 positivity alone was not predictive of clinical outcomes.17,18. The gene discussed is PDCD1; the disease is metastatic melanoma.