CTLA4 and infection: Additionally, when analyzed cumulatively for all three ICI classes, there was a statistically increased risk of ICIs when a co-occurring infection was present: PD-1 inhibitors 1.91 (1.74, 2.09), PD-L1 inhibitors 2.05 (1.64, 2.55), CTLA-4 inhibitor (ipilimumab) 1.70 (1.33, 2.18) (Figure 2).