9464D-GD2 is a “cold” neuroblastoma model with low mutational burden (15) and low MHC class I expression (24); mice with a small neuroblastoma (75 mm3 or less) show no response to a combination of RT + anti-CTLA-4 + anti GD2/IL-2 immunocytokine, and ~ 50% of mice bearing these small 9464D-GD2 tumors regress in response to a combined regimen using RT, immunocytokine, anti-CD40, CpG and anti-CTLA-4 (15, 24). Here, CTLA4 is linked to neuroblastoma.