CD4 and lung adenocarcinoma: As shown in Fig. 3A, the FGL2 expression level was positively correlated with B cell infiltration (r = 0.409, P = 5.79e−21), CD8+ T cell infiltration (r = 0.539, P = 1.37e−47), CD4+ T cell infiltration (r = 0.379, P = 1.97e−17), macrophage infiltration (r = 0.540, P = 3.87e−38) and dendritic cell infiltration (r = 0.718, P = 1.44e−78) in lung adenocarcinoma.