PDCD1 and neoplasm: By applying single cell RNA‐sequencing to a concurrent subcutaneous and liver tumor murine model to recapitulate liver metastases, it is identified that subsets within tumor‐infiltrating exhausted CD8+ T (Tex) cells and immunosuppressive tumor‐associated macrophages (TAMs) display opposite responses to concurrent liver tumors and anti‐PD‐1 treatment, suggesting a complex immune regulating network.