PDCD1LG2 and neoplasm: Whereas, the representative ICIs contain anti-PD-1 antibodies (such as pembrolizumab and nivolumab) that specifically bind to PD-1 on the surface of T cells and then reinvigorate the function of tumor-specific T cells via obstructing the PD-1/PD-L1 or PD-1/PD-L2 signaling pathways, and anti-PD-L1 antibodies (such as atezolizumab) which only block the PD-1/PD-L1 pathway, but do not affect the PD-1/PD-L2 pathway.