To further investigate the relationship between ISG15 and lymphocyte infiltration in lung adenocarcinoma, ISG15 and CD3+, CD4+, CD8+, CD45RA+, CD45RO+, CD20+, CD66b+, CD57+, Foxp3+, CD68+ microenvironmentally infiltrated lymphocytes were immunohistochemically stained in 153 prognostically intact LUAD samples (Additional file 1: Fig. S1, Additional file 2: Fig. S2, Additional file 3: Fig. S3 and Additional file 4: Fig. S4). Here, CD4 is linked to lung adenocarcinoma.