SLAMF7 and neuroblastoma: Collectively, our data support the hypothesis that macrophages are important effector cells in the anti-high-risk neuroblastoma immune response, that PD-1 blockade therapy can be beneficial to the high-risk neuroblastoma subset with the PD-1/PD-L1 ratio >1, and that SLAMF7 is a promising new therapeutic target of high-risk neuroblastoma.