PDCD1 and nonpapillary renal cell carcinoma: (36) identified that, compared to the normal renal samples and early ccRCC, a higher proportion of M2-like tumor-associated macrophages (TAMs) expressing ligands for multiple T-cell inhibitory receptors such as PD-1, CTLA-4, and TIGIT were enriched in advanced and metastatic ccRCC and were related to a worse prognosis.