PIK3CG and head and neck squamous cell carcinoma: Knockout phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma (PIK3CG) increased CD8+ T cell infiltration and programmed death 1 (PD-1) expression in T cells in the tumour microenvironment; thus, inhibiting p110γ enhanced the efficacy of anti-programmed cell death ligand 1 (PD-L1) immunotherapy in head and neck squamous cell carcinoma by modulating host immune activity against tumour cytotoxicity and increasing the expression of immunosuppressive markers (Anderson et al. 2021).