PIK3CD and neoplasm: Okkenhaug et al. (2016) and O’Donnell et al. (2018) provided extensive reviews on the recent findings of the immunomodulatory roles of PI3K pathway on the tumor microenvironment, including the enhanced expression of PD-L1, recruitment, and differentiation of myeloid-derived suppressor cells (MDSCs) and Tregs into the tumor, and secretion of suppressive cytokines to impair stimulation of macrophages and dendritic cells and the migration, expansion, functionality, and memory development of T cells (Okkenhaug et al., 2016; O’Donnell et al., 2018).