In addition, the high densities of tumor-infiltrating C1q+ TAMs in clear cell renal carcinoma (ccRCC) patients are significantly associated with an immunosuppressive microenvironment, which is characterized by the high expression of immune checkpoints (i.e., PD-1, LAG-3, PD-L1, and PD-L2). Here, PDCD1 is linked to clear cell renal carcinoma.