X0508 4 2025-05-30 0001865494 IO Biotech, Inc. IOBT 0001891841 Hunter Heidi C/O IO BIOTECH, INC. OLE MAALOES VEJ 3 COPENHAGEN G7 2200 DENMARK true false Common Stock 2025-05-30 4 P 0 15000 1.3923 A 15000 D The transaction was executed in multiple trades in prices ranging from $1.37 to $1.40, inclusive. The price reported in Column 4 above reflects the weighted average purchase price. The reporting person hereby undertakes to provide to the Securities and Exchange Commission staff, the Issuer, or a security holder of the Issuer, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote. /s/ Brian Burkavage, Attorney-in-Fact for Heidi Hunter 2025-06-02