Fig. 8

Working model for the effect of S100A9⁺CD14⁺ monocytes contribute to anti-PD-1 immunotherapy resistance. Abundant blood S100A9⁺CD14⁺ monocytes and high concentrate plasma S100A9 linked to poor HCC response to anti-PD-1. Mono_S100A9 signature inversely associated with survival of cancer patients. S100A9 enhanced PD-L1 expression on monocytes to inhibit T-cell proliferation and cytotoxicity. Blockage of S100A9 synergizes with anti-PD-1 drug to enhance HCC eradication