The analysis of effector memory cytotoxic T cells (Granzyme B, NKG2ACE, CD223, CD366, TIM-3, CD27, CD44, CD39, and expressing IFNγ), found in the tumors of PD-1Ab, PD-1KO, and PD-1cKO mice in our study, prior to tumor growth inhibition, contributes further to the knowledge of functional TILs that can contribute to long-term tumor immunity after PD-1 blockade. This evidence concerns the gene CD44 and neoplasm.