A recent meta-analysis, which included 36 head-to-head phase II and III randomized trials, showed that the most common drug-dependent toxicities are hypothyroidism, nausea, and vomiting for atezolizumab (anti-PD-L1 mAb), endocrine toxicities for nivolumab, arthralgia, pneumonitis and hepatic toxicities for pembrolizumab (anti-PD1 mAb), and dermatologic, gastrointestinal and renal toxicities for ipilimumab (anti-CTLA-4 mAb) (12). The gene discussed is CTLA4; the disease is hypothyroidism.