Jie Chen et al’s groundbreaking work unveiled that LAG-3 is overexpressed on CD4+ and CD8+ T cells in bronchoalveolar lavage fluid of TB patients, accompanied by reduced secretion of IFN-γ and granzyme B; furthermore, LAG-3 expression on CD8+ T cells correlates closely with the severity of TB (Chen et al., 2023). The gene discussed is CD4; the disease is tuberculosis.