CTLA4 and breast carcinoma: Indeed, Henau et al., reported that PI3K-γ inhibitor IPI-549 significantly enhanced CD8+ T cell activation and reduced immunosuppression and resistance to immune checkpoint therapy with anti-CTLA-4 or anti-PD-1/anti-PD-L1 by increasing the M1/M2 ratio in 4T1 breast carcinoma and B16-GM-CSF melanoma models [190].