This increased MHC II expression in myeloid cells in the bone marrow of tumor-bearing mice treated with a dual PI3Kγ/PD-L1 inhibitor suggests a systemic reprogramming of myeloid cells to promote terminal differentiation, immune activation and optimal priming of antitumoral T-cell responses against HNSCC. This evidence concerns the gene CD274 and head and neck squamous cell carcinoma.