Simultaneously, Mn2+ potentiated the dsDNA recognition by cGAS, amplifying STING pathway activation.[65b] Following intravenous administration, the combination of NaGdF4:Nd@NaLuF4 and Mn2+ under X‐ray irradiation demonstrated robust synergistic effects in a 4T1 tumor model. Here, CGAS is linked to neoplasm.