CD38 upregulation and high PD-1 expression on T cells has been seen as a mechanism of tumor cell resistance to ICIs [77, 78], and these findings of increased CD38 expression in CSF of LMD patients along with no response of T cell phenotype to ICI treatment lead to the concern that the underlying immune profile of LMD will likely limit the efficacy of ICI therapy. This evidence concerns the gene CD38 and neoplasm.