PTEN and neoplasm: As PI3K activation may occur via the loss of PTEN, it has been further reported that the loss of this tumor suppressor may induce the overexpression of PD-L1 and immunoresistance in several tumors of different histological origin (i.e., glioma, leiomyosarcoma, colorectal, breast cancer, and PDAC [118,119,120,121,122].