Representative image of H&E staining in (A) lung cancer (×40, ×200) and (B) brain metastasis specimens (×40, ×200). Multiplex immunofluorescence in (C) lung cancer and (D) brain metastasis specimens for the following markers: CD3, CD4, CD8, CD204, Foxp3, cytokeratin, and DAPI. Original magnification, ×20. Additional staining in (C), (D) illustrating associated singlet immunostaining of CD3, CD4, CD8, CD204, Foxp3, and cytokeratin. (E) Relationship of the density of each immune cell in the cancer area and the stromal area between lung cancer and brain metastasis specimens. CD204+, CD204-positive; CD4+, CD4-positive; CD8+, CD8-positive; DAPI, 4′,6-diamidino-2-phenylindole fluorescent stain; Foxp3+, Foxp3-positive; H&E, hematoxylin and eosin staining.