PDCD1 and neoplasm: Furthermore, it was also emphasized that the gut flora probably function in the modulation of PD1/PD-L1 blockade through bacteria translocation or sending bacteria-derived molecules to enhance antigenicity and endeavor anti-tumor immune response, which was proved by evidence that certain microbiota types were explicitly found to be enriched in ICI effective patients while some corresponded with the non-responsiveness of PD1/PD-L1 blockade (20–24).