CTLA4 and cancer: There is evidence suggesting that BRAF and MEK inhibition induces CD4 and CD8 T lymphocytes, boosting their cytotoxicity against cancer cells, which is evident by elevated granzyme B and perforin levels, and an elevated expression of cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) [111,129,130,131,132,133].