Fortunately, targeted therapy for another PD-1 ligand, PD-L2, might be considered in clinical practice, as the expression of PD-L2 is more pronounced compared to the rare expression of PD-1 or PD-L1 in small intestinal or pancreatic NETs [44,63]. This evidence concerns the gene PDCD1LG2 and pancreatic neuroendocrine tumor.