Private Placement (Form 8-K)

The disclosure regarding the Tranche A Warrant as set forth under Item 8.01 of this report is incorporated by reference under this Item 3.02.

The securities described below under Item 1.01 have not been registered under the Securities Act of 1933, as amended (the "Securities Act"). The Company relied on the exemption from the registration requirements of the Securities Act by virtue of Section 4(a)(2) thereof on the basis that the transaction did not involve a public offering.

As previously announced, on December 19, 2024, IO Biotech ApS, a private limited liability company incorporated in Denmark and wholly-owned subsidiary (the "Borrower") of IO Biotech, Inc., a Delaware corporation (the "Company") entered into a Finance Contract (the "Finance Contract") and a related side letter with the European Investment Bank ("EIB"), establishing three committed tranches and one uncommitted tranche of potential financing in an aggregate principal amount of up to €57.5 million, subject to certain conditions precedent.

Pursuant to the Finance Contract, the Company (through the Borrower) has satisfied the conditions to draw €10.0 million in an initial tranche of the term loan facility ("Tranche A"). In connection therewith, on April 24, 2025, the Company issued to EIB a Tranche A warrant (the "Tranche A Warrant") to purchase up to 5,623,664.38 shares of the Company's common stock, par value $0.001 (the "Common Stock"). The Strike Price (as defined in the Tranche A Warrant) per share of Common Stock is $0.8891. It is expected that the Company (through the Borrower) will draw down upon the Tranche A loan on or around May 6, 2025.

Except as disclosed herein, the terms and conditions under the Tranche A Warrant are as disclosed under the heading "Warrants" on our Form 8-Kfiled with the U.S. Securities and Exchange Commission on December 20, 2024.

The foregoing is only a summary of the terms of the Tranche A Warrant, does not purport to be complete and is qualified in its entirety by reference to the full text of the Tranche A Warrant, a copy of which is attached to this report as Exhibit 4.1.