STAT4 and head and neck squamous cell carcinoma: Since IL-12 enhances the phosphorylation of signal transducer and activator of transcription 4 (STAT4) in CAR-T cells and stimulates IFNγ release [22], local treatment with rAd-IL-12-PD-L1, which encodes a PD-L1-blocking antibody, and IL-12p70 was found to control both primary and metastasized head and neck squamous cell carcinoma in conjunction with HER2-specific CAR-T cells [190].