CD274 and melanoma: Guibert et al. found that NSCLC patients (n = 96) with PFS < 6 months had a higher baseline PD-L1+ CTC value (≥1%) during nivolumab treatment [43], whereas PD-L1+ CTCs showed a positive correlation with PFS in melanoma patients treated with pembrolizumab (n = 25) [44] and NSCLC patients treated with sintilimab combined with docetaxel (n = 30) [45].