PDCD1 and neoplasm: One preclinical study showed that combined treatment with anti-PD-1 and anti-CTLA-4 antibodies failed to block the growth and metastasis of 4T1 tumors, whereas cotreatment with DNMTi Azacitidine, anti-PD-1 and anti-CTLA-4 antibodies significantly improved treatment outcomes with more than 80% reduction in tumor burden (162).