Exhibit 5.1
Courtney M.W. Tygesson
+1 312 881 6680
ctygesson@cooley.com
June 18, 2026
Cue Biopharma, Inc.
40 Guest Street
Boston, MA 02135
Ladies and Gentlemen:
We have acted as counsel to Cue Biopharma, Inc., a Delaware corporation (the “Company”), in connection with the filing of a Registration Statement on Form S-3 (the “Registration Statement”) with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), including a related prospectus included in the Registration Statement (the “Prospectus”), covering the registration for resale of up to 551,724 shares (the “Warrant Shares”) of the Company’s common stock, par value $0.001 per share (“Common Stock”), issuable upon the exercise of pre-funded warrants to purchase shares of Common Stock (the “Warrants”). The Warrants were issued by the Company pursuant to that certain Securities Purchase Agreement, dated April 30, 2026, by and between the Company and Ascendant Health Sciences, Ltd. (the “Purchase Agreement”).
In connection with this opinion, we have examined and relied upon the Registration Statement, the Prospectus, the Company’s certificate of incorporation and bylaws, each as currently in effect, the Purchase Agreement, the form of the Warrants and such other records, documents, opinions, certificates, memoranda and instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to originals of all documents submitted to us as copies, the accuracy, completeness and authenticity of certificates of public officials and the due authorization, execution and delivery of all documents by all persons other than the Company. As to certain factual matters, we have relied upon a certificate of an officer of the Company and have not independently verified such matters.
Our opinion is expressed only with respect to the General Corporation Law of the State of Delaware. We express no opinion to the extent that any other laws are applicable to the subject matter hereof and express no opinion and provide no assurance as to compliance with any federal or state anti-fraud law, rule or regulation relating to securities or to the sale or issuance thereof.
With respect to the Warrant Shares, we express no opinion to the extent that future issuances of securities by the Company, adjustments to outstanding securities of the Company or other matters cause the Warrants to be exercisable for more shares of Common Stock than the number available for issuance by the Company, or that the consideration paid upon exercise of the Warrants is below the par value per share of the Common Stock.
On the basis of the foregoing, in reliance thereon and subject to the assumptions, exceptions, limitations and qualifications set forth herein, we are of the opinion that the Warrant Shares, when issued and paid for in accordance with the terms of the Warrants, will be validly issued, fully paid and nonassessable.
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