In fact, several studies underlined how the PI3K pathway is involved in the differentiation of myeloid-derived suppressor cells (MDSCs) and Tregs into the tumor as well as the secretion of suppressive cytokines to impair stimulation of macrophages and dendritic cells, leading to an immunosuppressive tumour microenvironment (TME) [8]. The gene discussed is PIK3CD; the disease is neoplasm.