In mouse melanoma models, tumor-infiltrating NK cells have higher TIGIT expression than NK cells in surrounding tissues, and TIGIT+ NK cells had lower IFNγ, TNF, CD107a, and TRAIL expression and exhibited greater apoptosis, demonstrating an exhausted phenotype, which could be relieved in TIGIT−/− tumor recipients or anti-TIGIT antibody blockade. The gene discussed is TNFSF10; the disease is neoplasm.