To test this in a model of metastatic disease, we randomized mice bearing a “primary” right flank MOC2 tumor and a “secondary” left flank MOC2 tumor to treatment with PBS control, anti-CTLA-4 and anti-PD-L1 dual immune checkpoint blockade (ICI), 12 Gy tumor dose from 90Y-NM600 (100 μCi injected activity), 12 Gy tumor dose delivered to the primary tumor via EBRT, 12 Gy tumor dose from 90Y-NM600 together with ICI, or 12 Gy tumor dose delivered to the primary tumor via EBRT together with ICI. Here, CTLA4 is linked to metastatic neoplasm.