Different monoclonal antibodies act at different stages. (a) acting on the upstream of PD-L2 can reduce the expression of PD-L2, such as Ganetespib; (b) Acting on the junction of PD-L2 and PD-1 can directly inhibit the function of PD-L2, such as Dostarlimab; (c) It can also be applied to PD-L2-RGMb. All these can inhibit the immune escape of tumor. Here, PDCD1 is linked to neoplasm.