CD8A and neoplasm: Meanwhile, tumors can be classified into different groups based on their programmed death-ligand 1/2 (PD-L1/PD-L2) status, the presence or absence of TILs with PD-L1/PD-L2, and the presence of antigen-specific CD8+ TILs that drive adaptive immune resistance, referred to as a “hot tumor” (10).