Furthermore, Sharma et al. [47] reported that, in the CheckMate 032 trial, grade 5 treatment-related pneumonitis occurred in two patients receiving nivolumab (PD-1 inhibitors) monotherapy (3 mg/kg), and nivolumab 3 mg/kg plus ipilimumab (CTLA-4 inhibitors) 1 mg/kg, respectively, compared with nivolumab 1 mg/kg plus ipilimumab 3 mg/kg. Here, CTLA4 is linked to pneumonitis.