In recent years, as immunotherapy has come to the forefront, ICB strategies have been applied to CRC treatment.18,19 For instance, PD-1, PD-L1, and members of the CD28 superfamily of T cell regulatory factors have been identified as potential targets for immunotherapy in CRC.20 Recently, research has shown that the microbiome can influence the effectiveness of cancer immunotherapy. Here, PDCD1 is linked to cancer.