Extended Data Fig. 1. Landscapes of MHC expression, distribution of tumour infiltrating CD8+ T cells, and single cell transcriptomes of human melanoma metastases.

a, Representative immunohistochemical stains of human melanoma skin metastases with high, intermediate and low expression of MHC-I. b, Left: Overviews of representative immunohistochemistry stainings for CD8 and magnifications of 0.1 mm² squares in the tumour center and at the tumour invasive margins that were evaluated for the number of infiltrating CD8+ T cells; Right: graphical illustration of the three distinct patterns of immune infiltration observed. c, Representative immunohistochemical stains of human melanoma skin metastases with high, intermediate and low expression of MHC-II. d, MHC-I and (e) MHC-II gene set expression in single melanoma cells of an additional set of human melanoma metastases in skin (n = 5), subcutis (n = 4), and lymph nodes (n = 11), categorised into ICB therapy responders and non-responders. Median MHC-I gene set expression was used to categorize tumours according to high (>0.75), intermediate (0.25 - 0.75) and low (<0.25) expression levels. f, Uniform manifold approximation and projection (UMAP) clustering of the immune cell compartment in human melanomas annotated as indicated. g, MHC-I (top) and MHC-II (bottom) gene set expression in the indicated immune cell subpopulations.