NKG7 (natural killer cell granule protein 7) is a type-I integral membrane protein 1 that serves as a critical regulator of cytotoxic lymphocyte function through two complementary mechanisms. Primarily, NKG7 mediates cytotoxic granule exocytosis in NK cells, CD8+ T cells, and activated CD4+ T cells by regulating translocation of CD107a to the cell surface and promoting release of perforin and granzymes 2. This function is essential for killing target cells during infection and cancer immunity. Recently, NKG7 was identified as a lysosomal protein that negatively regulates mTORC1 activity by inhibiting v-ATPase function, thereby promoting CD8+ T cell memory development and longevity 3. NKG7 expression marks activated, cytotoxic lymphocytes across diverse disease contexts, including parasitic infections, cancer, spinal cord injury, and inflammatory skin conditions 2456. Clinically, NKG7 expression on CD8+ T cells and MAIT cells correlates with responsiveness to anti-PD-1 immunotherapy in lung cancer 4, and NKG7 upregulation shows therapeutic potential in T cell-based cancer therapies 7. These findings establish NKG7 as both a functional mediator of immune responses and a promising biomarker for immunotherapy outcomes.