Nivolumab, another IgG4 PD-1 monoclonal antibody (BMS-936558, Bristol-Myers Squibb), received FDA approval in 2016 for R/M SCCHN with or without PD-L1 expression based on the results of the randomized, phase III CheckMate 141 trial by Ferris et al. [13]. Here, CD274 is linked to head and neck squamous cell carcinoma.