Several T cell populations were differentially abundant between HC, MF, and SS subjects, including a noticeable enrichment in CTCL patients for cells expressing cutaneous lymphocyte antigen (CLA), a receptor facilitating skin homing,12 and CD39, an ectoenzyme often upregulated on tumor-specific T cells13,14 (Figure S1N). This evidence concerns the gene ENTPD1 and primary cutaneous T-cell non-Hodgkin lymphoma.