AGREEMENT

EXHIBIT A

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of Common Stock of Gritstone bio, Inc.

Date:		September 21, 2021				XXXXXXX HEALTHCARE VII, L.P.
						By FHM VII, L.P., its general partner
						By FHM VII, L.L.C., its general partner
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				XXXXXXX HEALTHCARE VII-A, L.P.
						By FHM VII, L.P., its general partner
						By FHM VII, L.L.C., its general partner
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				FHM VII, L.P.
						By FHM VII, L.L.C., its general partner
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				FHM VII, L.L.C.
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				XXXXXXX LIFE SCIENCES PUBLIC FUND L.P.
						By: FHMLSP, L.P., its General Partner
						By: FHMLSP, L.L.C., its General Partner
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				FHMLSP, L.P.
						By: FHMLSP, L.L.C., its General Partner
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer

Date:		September 21, 2021				FHMLSP, L.L.C.
						By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, Chief Financial Officer
Date:		September 21, 2021				By:		*
								Xxxxx Xxxxxx
Date:		September 21, 2021				By:		*
								Xxxxxxx Xxxxx
Date:		September 21, 2021				By:		*
								Xxxxx Xxxxx
Date:		September 21, 2021				By:		*
								Xxxxxx Every
Date:		September 21, 2021				By:		*
								Xxxxx Xxxxxxx
Date:		September 21, 2021				By:		*
								Xxxx Xxxxxxx
Date:		September 21, 2021				By:		**
								Xxxxxx Xxx
Date:		September 21, 2021				By:		**
								Xxxxx Xxxxx
Date:		September 21, 2021				*By:		/s/ Xxxxx X. Xxxxxx
								Xxxxx X. Xxxxxx, as Attorney-in-Fact

* This Schedule 13G was executed by Xxxxx X. Xxxxxx on behalf of the individuals listed above pursuant to a Power of Attorney, a copy of which was filed with the SEC on March 29, 2016.

** This Schedule 13G was executed by Xxxxx X. Xxxxxx on behalf of the individuals listed above pursuant to a Power of Attorney, a copy of which was filed with the SEC on August 16, 2021.