EXHIBIT 23.3

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption “Experts” and to the use of our report dated February 28, 2022 incorporated by reference in this Registration Statement on Form S-4 of Sesen Bio, Inc. for the registration of shares of its common stock.

/s/ Ernst & Young LLP​

Boston, Massachusetts

February 14, 2023