The present invention relates to a method able to enhance survival and functionality of anti-tumor or anti-viral immune cells through overexpression of Akt molecules in the cells. Akt signaling prevented the expression of immune checkpoints and therefore rescued antigen-specific cytotoxic T lymphocytes from exhaustion in immunosuppressive microenvironment. This present invention also demostrated that AKT genes have the potential to be utilized in T-cell engineering of adoptive T-cell therapy for treatment of chronic viral infection and malignancies