Targeted therapy with BRAF and MEK inhibitors, or immune checkpoint blockade with a PD-1 antibody (nivolumab or pembrolizumab) as monotherapy, or PD-1 and CTLA-4 antibodies (nivolumab and ipilimumab) in combination, have been shown to improve progression-free survival (PFS) and overall survival (OS) for patients with advanced melanoma [14–18]. The gene discussed is CTLA4; the disease is melanoma.