scRNA-seq profiling in diagnostic and relapsed CHL. (A) Study cohort composition; overview of the discovery cohort used for targeted hybrid-capture sequencing; validation cohort 1 (targeted hybrid-capture sequencing); and validation cohort 2 (IHC and IMC). (B) UMAP visualization of all major immune cell populations across CHL and RLN samples in the discovery cohort. (C) Heat map showing the canonical marker expression in each cell cluster. (D) Proportional changes in B- and T-cell clusters between diagnostic and relapsed CHL samples in the discovery cohort. The white dashed line represents the expected ratio of cell proportions from relapse samples based on the total cell number of diagnostic and relapse samples. GCB, germinal center B cell; NK, natural killer cell; Th, T helper cell; Treg, regulatory T cell.