have engineered OMV‐PD1 to bind PD‐L1 on the surface of tumor cells and promote its internalization and reduction, thus reversing the inhibition of T‐cell proliferation in a way similar to anti‐PD‐L1 antibody therapy but in a much more cost‐effective manner.[209] OMV‐PD‐L1 has the immune stimulation ability of natural OMVs and can inhibit tumor growth in CT26 colorectal cancer mice and B16 melanoma mice with an immune memory that protects against tumor recurrence.[209]. Here, CD274 is linked to melanoma.