CD274 and neoplasm: Unlike MHC-I, PD-L1 was expressed on Y3.3UVRc34 but notably absent on YR1.7 tumor cells (Figure 3e), consistent with the lack of PD-L1 expression on YR1.7 cells exposed to IFNγ in vitro (Figure 1a); PD-L1 was expressed in the TME of both models.