In this study, which combined three different radiotherapy doses (1 × 20 Gy; 3 × 8 Gy; 5 × 6 Gy) with anti-CTLA-4 ICI, only the fractionated radiotherapy regimens (3 × 8 Gy and 5 × 6 Gy) resulted in significant primary (irradiated) and secondary (non-irradiated) tumor inhibition, whereas ICI administration alone had no effect on primary or secondary tumors, and radiotherapy alone affected only the primary tumors. The gene discussed is CTLA4; the disease is neoplasm.