Objectives: Immunotherapy combining agonists of the cyclic GMP-AMP synthase–stimulator of interferon genes (cGAS-STING) pathway with PD-1/PD-L1 blockade shows promising preclinical results, although in clinical practice, it faces pharmacokinetic barriers, systemic toxicity, and an immunosuppressive tumor microenvironment (TME). The gene discussed is CGAS; the disease is neoplasm.