CD4 and non-small cell lung carcinoma: Seven-color multiplex immunofluorescence (IF) staining of the specimens of 32 surgically resected NSCLC tumors who received ICB monotherapy revealed that the number of CD4+ T cells infiltrating the stroma (interstitium), but not the tumor parenchyma, was significantly higher in Meflin-high patients than in Meflin-low patients (Fig 5A).