PECAM1 and melanoma: At follow-up, anti-angiogenic effects of combined anti-PD-L1/anti-CTLA-4 immunotherapy were observed in the investigated melanoma allografts with a significantly lower microvascular density in combined anti-PD-L1/anti-CTLA-4-treated than in non-treated animals (CD31 142.1 ± 59.8 vs. 286.3 ± 88.1; p = 0.003), quantified by CD31 staining.