They also provide a rational design of combinatorial cancer immunotherapy harnessing a ppCT-based peptide vaccine, together with checkpoint inhibitors, in particular anti-PD-1 and anti-PD-L1 mAbs, to treat patients suffering from NSCLC, MTC and NET and to prevent outgrowth of immune-escaped cancer cells. This evidence concerns the gene CD274 and medullary thyroid gland carcinoma.