Exhibit 4.1

. ZQ|CERT#|COY|CLS|RGSTRY|ACCT#|TRANSTYPE|RUN#|TRANS# COMMON STOCK COMMON STOCK PAR VALUE $0.001 Certificate Shares Number * * 0 0 0 0 0 0 * * * * * * * * * * * * * * * * * * ZQ00000000 * * * 0 0 0 0 0 0 * * * * * * * * * * * * * * * * * * * * * 0 0 0 0 0 0 * * * * * * * * * * * * * * * * IO BIOTECH, INC. * * * * * 0 0 0 0 0 0 * * * * * * * * * * * * * * * INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE * * * * * * 0 0 0 0 0 0 * * * * * * * * * * * * * * ** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample SEE REVERSE FOR CERTAIN DEFINITIONS **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David THIS CERTIFIES THAT Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** r. Alexander David Sample **** r. Alexander David Sample **** Mr. Alexander David Sample **** Mr. MR. Alexander David SAMPLE ample **** Mr. Alexander David &Sample MRS. **** Mr. Alexander SAMPLE David Sample **** Mr. Alexander & David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr Alexander David Sample **** Mr. Alexander David Sample **** CUSIP 449778 10 9 Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander MR. David Sample SAMPLE **** Mr. lexander David Sample **** &Mr. Alexander MRS. David Sample SAMPLE **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** r. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Sample **** Mr. Sample is the owner of **000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares*** *000000**Shares *000000**Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares**** 000000**Shares 000000**Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares****0 THIS CERTIFICATE IS TRANSFERABLE IN 00000**Shares *** 000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000** ZERO HUNDRED THOUSAND hares****000000**Shares****00 0000**Shares *000000**Shares****000000**Shares****000000**Shares****000000 **Shares****000000**Shares****000000** hares****000000**Shares****000 CITIES DESIGNATED BY THE TRANSFER 000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000 Shares****0000 AGENT, AVAILABLE ONLINE AT 00**Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares****000000 Shares****00000 0**Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares****000000 ZERO HUNDRED AND ZERO*** Shares****000000 www.computershare.com **Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000 Shares****000000* *Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000** Shares****000000**Shares****000000**Shares****000000**Shares ****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**S FULLY-PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK OF IO Biotech, Inc. (hereinafter called the “Company”), transferable on the books of the Company in person or by duly authorized attorney, upon surrender of this Certificate properly endorsed. This Certificate and the shares represented hereby, are issued and shall be held subject to all of the provisions of the Certificate of Incorporation, as amended, and the By-Laws, as amended, of the Company (copies of which are on file with the Company and with the Transfer Agent), to all of which each holder, by acceptance hereof, assents. This Certificate is not valid unless countersigned and registered by the Transfer Agent and Registrar. Witness the facsimile seal of the Company and the facsimile signatures of its duly authorized officers. DATED DD-MMM-YYYY FACSIMILE SIGNATURE TO COME I O TECH, I COUNTERSIGNED AND REGISTERED: B RPORA N COMPUTERSHARE TRUST COMPANY, N.A. President I OC O T E C . TRANSFERAGENT ANDREGISTRAR, 5/25/2021 FACSIMILE SIGNATURE TO COME DELAW A R E Secretary By 01:06                QTA                Page 35 AUTHORIZED^SIGNATURE    CUSIP/IDENTIFIER XXXXXX XX X Holder ID XXXXXXXXXX Insurance Value 00.1,000,000 Number of Shares 123456 DTC 12345678901234512345678    PO BOX 505006, Louisville, KY 40233-5006 Certificate Numbers Num/No Denom. Total. MR DESIGNATION A SAMPLE (IF ANY) 1234567890/12345678901234567890/1234567890 121212 ADD 1 1234567890/12345678901234567890/1234567890 343434 ADD 2 ADD 3 ADD 4 1234567890/12345678901234567890/1234567890 565656 Total Transaction 7