CD274 and neoplasm: In the tumor microenvironment, tumor cells or immunosuppressive cells highly express PD-L1, which, upon binding to PD-1 on T cells, transmits inhibitory signals, leading to T-cell exhaustion and impaired proliferation, thereby facilitating tumor evasion from immune recognition and clearance (Cheng W. et al., 2024; Cheng et al., 2022; Figure 1).