CD274 and head and neck squamous cell carcinoma: Our dual treatment targeting PI3Kγ and PD-L1 was more effective than single treatment, as evidenced by a significant increase in MHC II expression in both M1 and M2 macrophages within the tumor microenvironment and spleen of HNSCC tumor-bearing mice following dual IPI-549/anti-PD-L1 treatment, effectively restoring these immune cells to an antitumoral phenotype.