PDCD1 and non-small cell lung carcinoma: In KrasG12D/+; p53-/- NSCLC mouse model, it was further demonstrated that αPD-1 antibodies fail to synergize with anti-angiogenic agents to enhance antitumor effects, with the underlying resistance mechanism closely tied to macrophage-driven accumulation of PD-1+Tregs within the TME (51).