In addition, based on a phase II basket trial of anti-CTLA-4 (ipilimumab) and anti-PD-1 (nivolumab) co-blockade, patients with high-grade neuroendocrine carcinomas (NEC) had an ORR of 44% (8/18 patients) vs. 0% in low/intermediate grade NET (0/14 patients; p = 0.004) (8), while among 40 NEN patients enrolled in a multiple-center phase Ib trial of anti-PD-1 (toripalimab), poorly-differentiated NEC and well-differentiated NET subgroups had similar response rates (ORR: 18.7% vs. 25.0%) (9). This evidence concerns the gene PDCD1 and neuroendocrine carcinoma.