PDCD1 and primary cutaneous T-cell non-Hodgkin lymphoma: identified topographical differences ineffector PD‐1+ CD4+ T cells, tumor cells, and Tregs between responders and non‐responders, deriving a spatial biomarker, SpatialScore, which strongly correlates with pembrolizumab response in cutaneous T cell lymphomas (CTCL).[247] Tumeh et al.