In the melanoma cohort, PD-1 blockade responders (R) had significantly higher enrichment scores for the CD4+_MKI67 signature (p = 0.025) and the CD4+_CXCL13 signature (p = 0.05) than nonresponders (NR) did (Fig. 8D), indicating the predictive value of this cell population. Here, CXCL13 is linked to melanoma.