In addition to tumor cells, PD-L1 is rampantly expressed on fibroblasts [118], dendritic cells, macrophages, and B and T cells [39] and their effects on diminishing CAR-T cell function is highlighted as overexpression of PD-L1 and PD-L2 on tumor cells inhibits CAR-T cell function [119]. Here, PDCD1LG2 is linked to neoplasm.