FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Expires: December 31, 2014 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person * SCHULMAN AMY W (Last) (First) (Middle) 200 ARSENAL YARDS BLVD, SUITE 210 (Street) WATERTOWN MA 02472 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol SQZ Biotechnologies Co [ SQZ ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 12/22/2021
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	12/22/2021		M (1)		10,091	A	$ 2.02	200,775	D
Common Stock	12/22/2021		M (1)		7,458	A	$ 4.59	208,233	D
Common Stock	12/22/2021		M (1)		6,581	A	$ 4.59	214,814	D
Common Stock								275,860	I	See footnote (2)
Common Stock								178,340	I	See footnotes (3) (4)
Common Stock								2,549,306	I	See footnotes (4) (5)
Common Stock								1,850	I	See footnote (6)
Common Stock								1,850	I	See footnote (7)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option	$ 2.02	12/22/2021		M (1)			10,091	(8)	03/04/2028	Common Stock	10,091	$ 0	439	D
Stock Option	$ 4.59	12/22/2021		M (1)			7,458	(9)	02/18/2029	Common Stock	7,458	$ 0	3,072	D
Stock Option	$ 4.59	12/22/2021		M (1)			6,581	(10)	06/05/2029	Common Stock	6,581	$ 0	3,949	D

Explanation of Responses:

1. Options were exercised and held for tax planning purposes.

2. These shares are held of record by LS Polaris Innovation Fund, L.P. ("LSPIF"). LS Polaris Innovation Fund GP, L.L.C. ("LSPIF GP") is the general partner of LSPIF. The Reporting Person is the sole managing member of LSPIF GP. Each of LSPIF GP and the Reporting Person may be deemed to have sole investment, voting and dispositive power over these shares. LSPIF GP and the Reporting Person disclaim beneficial ownership of the shares held by LSPIF and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

3. These shares are held of record by Polaris Entrepreneurs' Fund VII, L.P. ("EF VII"). Polaris Management Co. VII, L.L.C. ("PMC VII") is the general partner of EF VII. David Barrett, Brian Chee, Amir Nashat and Bryce Youngren (the "Managing Members") are the managing members of PMC VII. The Reporting Person, a member of the Issuer's board of directors, holds an interest in PMC VII.

4. Each of the Managing Members and the Reporting Person, in their respective capacities with respect to PMC VII, may be deemed to have shared investment, voting and dispositive power over these shares. Each of PMC VII, the Managing Members and the Reporting Person disclaim beneficial ownership of these shares and this report shall not be deemed an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interests therein.

5. These shares are held of record by Polaris Partners VII, L.P. ("PP VII"). PMC VII is the general partner of PP VII. The Managing Members are the managing members of PMC VII. The Reporting Person, a member of the Issuer's board of directors, holds an interest in PMC VII.

6. These shares are held in trust 1 for the benefit of a child of the reporting person. The reporting person's spouse has investment authorization over the trust. The reporting person disclaims beneficial ownership of these securities, and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

7. These shares are held in trust 2 for the benefit of a child of the reporting person. The reporting person's spouse has investment authorization over the trust. The reporting person disclaims beneficial ownership of these securities, and the filing of this report is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.

8. The option vests and becomes exercisable as to 25% of the underlying securities on January 23, 2019 and in 36 equal monthly installments thereafter.

9. The option vests and becomes exercisable as to 25% of the underlying securities on February 1, 2020 and in 36 equal monthly installments thereafter.

10. The option vests and becomes exercisable in 48 equal monthly installments commencing on July 5, 2019.

	/s/ Lawrence Knopf, Attorney-in-Fact for Amy W. Schulman	12/23/2021
	** Signature of Reporting Person	Date
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