PDCD1 and cancer: Patients with cancer usually have a large number of T cells, which are often not at an optimal state due to immune tolerance and immunosuppressive mechanisms, and differentiate into a dysfunctional state called “depletion.”[35] In this study, PPM1M was found to be positively associated with some of the immune-activating and immune-suppressing genes that deplete T cells in pan-cancer, such as ENTPD1, CD48, CD28, CD86, HAVCR2, TIGIT, PDCD1, LAG3, CTLA4, and CD96.