These results differ from reports showing that CSF-1R+ elimination can enhance the efficacy of immunotherapy and cause tumor elimination in other cancer types.51 57 The minor effect of PLX3397 compared with trametinib in sensitizing tumors to αPD-1 highlights the fact that downregulating CSF-1 is only a part of the pleiotropic role played by trametinib in anti-cancer immunity. Here, CSF1 is linked to cancer.