CD274 and renal pelvis/ureter urothelial carcinoma: Type II tumors might be considered to show innate immune resistance, which means that constitutive activation of oncogenic signaling up-regulates PD-L1 expression by tumor cells in the tumor microenvironment independently of inflammatory signals [14, 38], suggesting that the pathways up-regulating PD-L1 are not so highly activated in type II UTUC.