SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Xilio Therapeutics, Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

28422T209

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP Number(s):

28422T209

Names of Reporting Persons

ORBIMED ADVISORS LLC

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 642,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 642,000.00

Aggregate Amount Beneficially Owned by Each Reporting Person

642,000.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

9.99 %

Type of Reporting Person (See Instructions)

SCHEDULE 13G

CUSIP Number(s):

28422T209

Names of Reporting Persons

OrbiMed Capital GP X LLC

Check the appropriate box if a member of a Group (see instructions)

(a)

(b)

Sec Use Only

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 481,500.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 481,500.00

Aggregate Amount Beneficially Owned by Each Reporting Person

481,500.00

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in row (9)

7.49 %

Type of Reporting Person (See Instructions)

SCHEDULE 13G

Item 1.

(a)

Name of issuer:

Xilio Therapeutics, Inc.

(b)

Address of issuer's principal executive offices:

828 Winter Street Waltham, MA 02451

Item 2.

(a)

Name of person filing:

OrbiMed Advisors LLC ("OrbiMed Advisors"), a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended. OrbiMed Capital GP X LLC ("OrbiMed GP" and together with OrbiMed Advisors, the "Reporting Persons"), a limited liability company organized under the laws of Delaware.

(b)

Address or principal business office or, if none, residence:

601 Lexington Avenue, 54th Floor New York, NY 10022

(c)

Citizenship:

Please refer to Item 4 on each cover sheet for each filing person.

(d)

Title of class of securities:

Common Stock, par value $0.0001 per share

(e)

CUSIP Number(s):

28422T209

Item 3.

If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:

(a)

Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);

(b)

Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);

(c)

Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);

(d)

Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);

(e)

An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f)

An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g)

A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h)

A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i)

A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j)

A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:

(k)

Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

Item 4.

Ownership

(a)

Amount beneficially owned:

OrbiMed Advisors: 642,000 OrbiMed GP: 481,500

(b)

Percent of class:

OrbiMed Advisors: 9.99% OrbiMed GP: 7.49%

(c)

Number of shares as to which the person has:

(i) Sole power to vote or to direct the vote:

OrbiMed Advisors: 0 OrbiMed GP: 0

(ii) Shared power to vote or to direct the vote:

OrbiMed Advisors: 642,000 OrbiMed GP: 481,500

(iii) Sole power to dispose or to direct the disposition of:

OrbiMed Advisors: 0 OrbiMed GP: 0

(iv) Shared power to dispose or to direct the disposition of:

OrbiMed Advisors: 642,000 OrbiMed GP: 481,500

Item 5.

Ownership of 5 Percent or Less of a Class.

Not Applicable

Item 6.

Ownership of more than 5 Percent on Behalf of Another Person.

If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.

The Reporting Persons hold 9.99% of the shares of Common Stock upon conversion of warrants in the aggregate on behalf of other persons who have the right to receive or the power to direct the receipt of dividends from, or proceeds from the sale of, such securities. OrbiMed Advisors exercises investment and voting power over the shares of Common Stock through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares of Common Stock reported herein.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.

Not Applicable

Item 8.

Identification and Classification of Members of the Group.

Not Applicable

Item 9.

Notice of Dissolution of Group.

Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

ORBIMED ADVISORS LLC

Signature:	/s/ Carl L. Gordon
Name/Title:	Carl L. Gordon/Member
Date:	05/15/2026

OrbiMed Capital GP X LLC

Signature:	/s/ Carl L. Gordon
Name/Title:	Carl L. Gordon/Member of OrbiMed Advisors LLC
Date:	05/15/2026

SEC Form SCHEDULE 13G filed by Xilio Therapeutics Inc.