To study the detailed mechanisms affecting this immunotherapy, Highfill et al. [70] developed a model of rhabdomyosarcoma in mice and found that the accumulation of CXCR2+CD11b+Ly6Ghi MDSCs in the tumor bed was the root cause limiting the efficacy of PD1 checkpoint blockade in cancer. Here, CXCR2 is linked to neoplasm.