Immunohistochemical (IHC) staining was performed on TMAs using the following primary antibodies: PD-L1 (1:200, 4.37 µg/mL, 13684, Cell Signaling Technology), B7-H3 (1:400, 1.49 µg/mL, 14 058S, Cell Signaling Technology), B7-H4 (1:400, 0.66 µg/mL, 14572, Cell Signaling Technology) and VISTA (1:200, 0.05 µg/mL, 54979, Cell Signaling Technology).15–18 (link) TMA slides were stained using standard immunohistochemistry techniques as previously described.15 (link) The IHC staining was scanned using Pannoramic MIDI (3D HISTECH). The histoscore of the membrane and nuclear staining quantification was assessed according to the formula (3+ per cent cells)×3+(2+per cent cells)×2+(1+per cent cells)×1, and the formula total intensity/total cell number was used to assess the histoscore of pixel quantification. In this case, the normalized score is between 0 and 300. This method has previously been described.19 (link)