Conversely, Wei et al. found CD8+PD1+ T cells were expanded in PBMC samples of melanoma patients treated with Nivolumab, Pembrolizumab, or Ipilimumab (a CTLA4 inhibitor) monotherapy, but the effects of these immunotherapies on CD4+PD1+ T cells were not well-characterized40. Here, CTLA4 is linked to melanoma.