Genomic analysis in CTCL patients identifies new genetic drivers and mutational signatures shared by MF and SS samples (see Figures 2 and 3 in the article by Park et al that begins on page 1225). A multimodal analysis using TCR ex vivo stimulation of malignant cells and TCR-dependent functional analyses shows that PD-1 loss leads to reversal of T-cell exhaustion signatures in humans and mice and is associated with a worse prognosis (see Figures 4 and 6 in the article by Park et al). The figure was prepared by Natalia Yanguas-Casas, using Figures 2, 3G, 4G, and 6D in Park et al. KO, knockout; Tfh, T follicular helper; Th, T helper; Trm, tissue-resident memory T cell; WT, wild-type. Putative oncogenes and tumor suppressors are indicated by red and blue boxes, respectively. *Indicates genes not previously reported in CTCL.