Based on previously written, we conducted a prospective study to investigate different subpopulations of immune cells, such as CD3+ cells, CD8+ cells, CD68+ cells, CD20+ cells, and FoxP3+ cells, and the expression of molecules, including LAG-3, IDO1, and TGFβ, by immunohistological staining in patients with advanced malignant melanoma and NSCLC, and assessed their role in ICI effectiveness. The gene discussed is FOXP3; the disease is non-small cell lung carcinoma.