The invention relates to a combination medicament for treatment of malignant neoplastic disease. The combination medicament comprises an IL-12 polypeptide having a biological activity of IL-12 or a nucleic acid expression vector comprising a sequence encoding such IL-12 polypeptide, and a non-agonist blockade of T-cell inhibitory molecules, including non-agonist LAG-3 ligand, non-agonist TIM-3 ligand, non-agonist BLTA ligand, non-agonist TIGIT ligand, non-agonist VISTA ligand, non-agonist B7/H3 ligand, non-agonist CTLA-4 ligand or non-agonist PD-1 ligand, particularly an anti-CTLA-4 or anti-PD-1 immunoglobulin G.