Schematic representation of sample collection and processing. Single or multiple punch biopsy specimens (4 mm) and 10 mL total blood were collected from 29 patients. In 7 patients, we collected >1 biopsy specimen (green silhouettes), and 3 patients were followed longitudinally with several biopsies and/or blood samples. The skin biopsy specimens were cryosectioned and used for laser microdissection of clusters of tumor cells, which along with blood PBMCs were processed for WES. Sequenced data were analyzed to identify rearranged CDR3 sequences of TCRA, TCRB, and TCRG and determine tumor cell fraction. Rectangles represent DNA fragments, green areas represent exons, and yellow areas represent rearranged TCR genes.