PDCD1 and neoplasm: The pivotal influence of the gut microbiota on the immune system has prompted investigations into its effects on the tumor microenvironment, thereby shaping tumor susceptibility to various therapeutic modalities, including immunotherapy (Ting et al. 2022).Numerous studies have underscored the substantial impact of gut microbiome composition on the efficacy of anticancer immune surveillance, particularly in the context of PD-1/PD-L1 and CTLA-4-based therapies (Guo et al. 2021).