Retrospective studies in matched cohorts of patients with melanoma [169, 170, 171], NSCLC [172, 173], and metastatic squamous cell carcinoma of the esophagus [174] have found that immune checkpoint inhibitor (ICI) medications ipilimumab (anti‐CTLA‐4), nivolumab (anti‐PD1), and pembrolizumab (anti‐PD1) demonstrated improved efficacy when administered in the morning compared to evening administration. The gene discussed is CTLA4; the disease is melanoma.