Next, we investigated the underlying mechanism by examining the effects of anti-PD-L1 and anti-VEGF treatment on the activation of immune cells in the whole brain and in the CLNs, which have been reported as draining lymph nodes for brain tumors, including brain metastatic lesions, and as draining lymph nodes for cerebrospinal fluid filling the lumen of the ventricles [31–34]. Here, CD274 is linked to brain neoplasm.