Furthermore, the ccRCC tumors infiltrated with high densities of C1q-producing tumor-associated macrophages revealed an immunosuppressed microenvironment, characterized by high expression of immune checkpoints (i.e., PD-1, Lag-3, PD-L1, and PD-L2), and associated poor clinical outcome. Here, PDCD1LG2 is linked to nonpapillary renal cell carcinoma.