CD8A and neoplasm: Since PD-1 is expressed much more prominently within tumors than in the periphery23,24, in the present study, we developed a low-affinity IL-12 mutant fused with a high-affinity anti-PD-1 antibody to enhance its specific binding to tumor-infiltrating PD-1+CD8+T cells rather than peripheral T or NK cells through cis-delivery.