While universal screening may not be cost-effective in all settings, targeted testing should be considered for patients with a personal or family history of autoimmune thyroid disorders, populations with a higher prevalence of thyroid autoimmunity, and those receiving combination ICI regimens (e.g., anti-CTLA-4 plus anti-PD-1), which carry higher thyroid irAE risks. The gene discussed is CTLA4; the disease is autoimmune thyroid disease.