MHC-I expression correlated with tumor surface expression of MHC class II (MHC-II) (Figure 1f, Supplementary Figures S1d–e and S2a–b) and the PD-1 ligand PD-L1 (Figure 1f, Supplementary Figure S2c–e), with considerable yet not complete overlap between MHC-I, MHC-II and PD-L1 low/negative tumors (Figure 1g). The gene discussed is PDCD1; the disease is neoplasm.