IFNG and small cell lung carcinoma: Even though there was no evidence to claim the upregulated expression of ligands for alternative checkpoints such as TIM-3 and LAG3 on stem-like subpopulation of SCLC cells, the expression of these ligands such as Galectin-3 and Galectin-9 are regulated by inflammatory cytokines such as IFN-γ thus widely expressed on immune cells together with LAG3 ligand HLA-DR expression on monocytes/macrophages [59–61].