0001782303 2025-05-09 2025-05-09 false 0001782303 8-K 2025-05-09 Boundless Bio, Inc. DE 001-41989 83-0751369 10955 Alexandria Way, Suite 100, San Diego CA 92121 (858) 766-9912 N/A false false false false Common Stock, par value $0.0001 per share BOLD NASDAQ true false