Initial Registration Statement for Employee Benefit Plan (Form S-8)

As filed with the Securities and Exchange Commission on March 23, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

PYXIS ONCOLOGY, INC.

(Exact name of registrant as specified in its charter)

Pyxis Oncology, Inc. 2021 Equity and Incentive Plan, as amended

Apexigen, Inc. 2022 Equity Incentive Plan

(Full title of the plan)

Jitendra Wadhane

Principal Financial and Accounting Officer

321 Harrison Avenue
Boston, Massachusetts

(617) 453-3596

(Name, address, and telephone number, including area code, of agent for service)

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

EXPLANATORY NOTE

This Registration Statement on Form S-8 is being filed for the purpose of registering (a) an additional 3,134,511 shares of common stock, par value $0.001 per share (the "Common Stock"), of Pyxis Oncology, Inc., a Delaware corporation (the "Company" or the "Registrant"), to be issued pursuant to the Pyxis Oncology, Inc. 2021 Equity and Incentive Plan, as amended (the "2021 Plan"), which Common Stock is in addition to the shares of Common Stock registered on the Registrant's Registration Statement on Form S-8 filed with the Securities and Exchange Commission (the "Commission") on October 22, 2021 (File No. 333-260441), March 29, 2022 (File No. 333-263950), March 22, 2023 (File No. 333-270753), March 22, 2024 (File No. 333-278159), November 12, 2024 (File No. 333-283161) and March 18, 2025 (File No. 333-285889) (b) 540,703 additional shares of Common Stock available for issuance under the Apexigen, Inc. 2022 Equity Incentive Plan (the "2022 Plan"), which Common Stock is in addition to the shares of Common Stock registered on the Registrant's Registration Statement on Form S-8 filed with the Commission on August 23, 2023 (File No. 333-274178), March 22, 2024 (File No. 333-278159) and March 18, 2025 (File No. 333-285889) (collectively, the "Prior Form S-8s").

This Registration Statement on Form S-8 relates to securities of the same class as that to which the Prior Form S-8s relate, and is submitted in accordance with General Instruction E to Form S-8 regarding Registration of Additional Securities. Pursuant to General Instruction E of Form S-8, the contents of the Prior Form S-8s, to the extent relating to the registration of Common Stock issuable under the 2021 Plan and 2022 Plan, as applicable, are incorporated herein by reference and made part of this Registration Statement on Form S-8, except as amended hereby.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

The Registrant hereby incorporates by reference in this Registration Statement the following documents and information previously filed with the Commission:

All documents subsequently filed by the Registrant with the Commission pursuant to Sections 13(a), 13(c), 14, and 15(d) of the Securities Exchange Act of 1934, as amended, prior to the filing of a post-effective amendment to this Registration Statement which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference into this Registration Statement and to be a part hereof from the respective dates of filing of such documents (such documents, and the documents enumerated above, being hereinafter referred to as "Incorporated Documents").

Any statement contained herein or in an Incorporated Document shall be deemed to be modified or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently filed Incorporated Document modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement.

Notwithstanding the foregoing, unless specifically stated to the contrary, none of the information disclosed by the Registrant under Items 2.02 or 7.01 of any Current Report on Form 8-K, including the related exhibits under Item 9.01, that the Registrant may from time to time furnish to the Commission will be incorporated by reference into, or otherwise included in, this Registration Statement.

Item 8. Exhibits.

The following exhibits are incorporated herein by reference:

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, State of Massachusetts, on March 23, 2026.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Thomas Civik and Jitendra Wadhane and each of them, as such person's true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for such person and in such person's name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this this Registration Statement and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith and about the premises, as fully to all intents and purposes as such person might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or any of them, or their or such person's substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.