CD226 and lung adenocarcinoma: Although previous studies have reported a high expression of TIGIT in lung adenocarcinoma (LUAD),11, 12 the role of TIGIT in the immune response of CD8+ T cells and their functional exhaustion remains elusive; in particular, the molecular and functional relationship between TIGIT/CD96/CD226 in the immune microenvironment of LUAD merits further research.