We observed a notable correlation between HPDL expression and a variety of infiltrating immune cells, including macrophages, B cells, cancer-associated fibroblasts (CAFs), and CD8+ T cells, in lung adenocarcinoma (LUAD), thymic carcinoma (THYM), and testicular germ cell tumors (TGCTs). The gene discussed is HPDL; the disease is thymic carcinoma.