The study from A. Palazon et al. shows that hypoxia-inducing transcription factor-1α (HIF-1α) in hypoxic tumors induces the expression of CD137 on TILs [41] and local intratumoral low-dose injection of agonist anti-CD137 mAb elicited systemic tumor-specific effector T cells capable of eradicating distant metastases. The gene discussed is HIF1A; the disease is neoplasm.