PDCD1 and neoplasm: Recently Smad4‐deficient mouse PDACs were found highly sensitive to a combination immunotherapy regimen (regimen consisting of gemcitabine (G), abraxane (A), CD40 agonistic antibody (F), CTLA4‐blocking antibody (C), and PD‐1‐blocking antibody (P), referred to as GAFCP), mimicking a regimen currently undergoing clinical trial (NCT03214250).[16a] Such findings also suggest that SMAD4 status should be evaluated as a potential biomarker for tumor response to such therapy.