Power of Attorney

The undersigned, a managing partner of The Column Group II Management LP, hereby
constitutes and appoints each of Gary A. Jungels, Jennifer J. Carlson, Leslie
Schmidt and Christine McDevitt, for so long as they are affiliated with a law
firm representing The Column Group, LLC, the undersigned's true and lawful
attorney-in-fact, each with the power to act alone for the undersigned and in
the undersigned's name, place and stead, to:

1. Prepare, complete and execute an SEC Form ID required by Sections 13(a) and
23(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
and the rules and regulations promulgated thereunder, and any and all amendments
thereto, and any other documents necessary or appropriate in order to obtain
EDGAR access codes, and to file or cause to be filed the same with the
Securities and Exchange Commission as may be required or advisable;

2. Prepare, complete and execute Forms 3, 4 and 5 under the Exchange Act and
other forms and all amendments thereto on the undersigned's behalf as such
attorney-in-fact shall in his or her discretion determine to be required or
advisable pursuant to Section 16 or Section 13 of the Exchange Act and the rules
and regulations promulgated thereunder, or any successor laws and regulations,
as a consequence of the undersigned's beneficial ownership of securities or
changes in such beneficial ownership; and

3. Do all acts necessary in order to file such forms and amendments with the
Securities and Exchange Commission, any securities exchange or national
association and such other persons or agencies as the attorney-in-fact shall
deem appropriate.

The undersigned hereby ratifies and confirms all that said attorneys-in-fact and
agents shall do or cause to be done by virtue hereof. The undersigned
acknowledges that the foregoing attorneys-in-fact, in serving in such capacity
at the request of the undersigned, are not assuming any of the undersigned's
responsibilities to comply with or liability under Section 16 or Section 13 of
the Exchange Act or any rules and regulations promulgated thereunder or any
successor laws and regulations.

This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file Forms 3, 4, or 5 or such other forms
and amendments thereto pursuant to Section 16 or Section 13 of the Exchange Act
with respect to the undersigned's beneficial ownership of securities or changes
in such beneficial ownership, unless earlier revoked by the undersigned in a
signed writing delivered to the foregoing attorneys-in-fact.

The undersigned has executed this Power of Attorney as of July 28, 2019.

							/s/ Peter Svennilson
							    Managing Partner