PDCD1 and neoplasm: This seemingly paradoxical phenomenon likely reflects the complexity of the tumor microenvironment (TME): a higher immune score may not simply indicate enhanced anti-tumor immunity but is more likely associated with the enrichment of immunosuppressive cell populations (such as regulatory T cells [Tregs] and M2-type tumor-associated macrophages [TAMs]) or elevated expression of co-inhibitory molecules (PD-1/PD-L1).