CD274 and cancer: On the other hand, although previous reports have shown that PD-L1 expression is induced in response to IFN-γ signaling85,86, CTLs and NK cells are more exhausted and express less IFN-γ in mixed and mesenchymal cSCCs, which may preclude the IFN-γ-mediated stimulation of PD-L1 expression in hybrid E/M and mesenchymal cancer cells.