It is well known that macrophage M2 type polarization, T regulatory (Treg) cells and MDSC cells can facilitate the advancement of lung adenocarcinoma, and Th2 helper cells can help the tumor immune escape process, however, CD8+ T cells and cytotoxic T cells, etc. are the main force of anti-tumor immunity (Anderson and Simon, 2020). The gene discussed is CD8A; the disease is lung adenocarcinoma.