CD274 and lung carcinoma: Encouraging clinical benefits of PD-1/PD-L1 checkpoint blockade have been demonstrated in over 15 different malignancies, among which melanoma [8–10], lung cancer [11, 12], genitourinary tract cancer [13], Hodgkin lymphoma [13] and sarcoma [14] confirming that host immune responses are essential in most neoplasms [15].