PDCD1 and neoplasm: In our study, the better efficacy of PD-1 antibody in the treatment of MSS-type CRC was associated with the glycerophospholipid metabolic pathway, while the metabolomics metabolite pathway enrichment was enriched in the glycerophospholipid metabolic pathway, accompanied by intergroup changes in the expression levels of IFN-γ and IL-2 in the tumor microenvironment.