PDCD1 and metastatic melanoma: With scRNA+TCRαβ-Seq, we profiled 18 peripheral blood (PB) samples from 5 IO-naive and 1 IO-refractory patients with metastatic melanoma treated with anti–LAG-3+anti–PD-1 combination therapy (CRs n = 2, PRs n = 1, PD n = 3; patient details are provided in Supplemental Table 1).