PDCD1 and neoplasm: In humanized PD-1 and LAG-3 knockin mice, in which the extracellular domains of mouse Pdcd1 and LAG-3 were replaced with their human counterparts, treatment with fianlimab improved the antitumor immune efficacy of cemiplimab, with enhanced secretion of proinflammatory cytokines by tumor-specific T cells (10).