Besides T cell activation, anti-CTLA4/anti-PD1 treatment also induced endothelial activation, as shown by increased expression of intercellular adhesion molecule (ICAM)-1 (% mean fluorescence intensity: control 100.0 ± 17.94 vs. ICI 160.7 ± 15.72; p = 0.023) (Figures 5A to 5C) and vascular cell adhesion molecule (VCAM)-1 (% mean fluorescence intensity: control 100.0 ± 27.61 vs. ICI 223.9 ± 18.26; p = 0.016), on aortic endothelium of the abdominal aorta, which represents the most initial phase of atherosclerosis before immune cell infiltration has commenced (Figures 5D and 5E). Here, CTLA4 is linked to atherosclerosis.