To improve the bioavailability of therapeutic antibodies aimed at inhibiting immune checkpoint molecules, HEK 293 cell-derived EVs overexpressing CD64 and the high-affinity Fc receptor of IgG have been coupled with the anti-PD-L1 antibody, improving the stability and bioavailability of the antibody to the tumor, and showing an anti-tumor effect in vivo against melanoma, with the proliferation of Tc cells and inhibition of Treg cells [157]. Here, CD274 is linked to neoplasm.