Although the abscopal effect after RT without any systemic treatment is rarely seen, the advent of immune checkpoint inhibitors (ICIs), which amplify anti-tumor immune responses by blocking negative immune regulators such as PD-1 and CTLA-4, has significantly heightened interest in the synergy between RT and ICIs, due to the capacity of RT to induce anti-tumor immune responses. This evidence concerns the gene CTLA4 and neoplasm.