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ARCUS BIOSCIENCES, INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

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The following email communication was first sent or made available to certain stockholders of Arcus Biosciences, Inc. on May 27, 2019:

Dear                         ,

You may have seen the ISS proxy report recommending stockholders “withhold” their votes to re-elect Yasunori Kaneko due to our classified board structure and certain other governance measures that we implemented in connection with Arcus’s IPO. While we understand ISS’s view that these measures can adversely impact shareholder rights, we also feel that this promotes continuity and stability so that we can focus on our long-term goals for the company. We hope that you will vote for each of our 2 directors up for re-election (Yasunori Kaneko, M.D., and Kristen Hege, M.D.), as well as for ratification of Ernst & Young as our independent auditors. If you have any questions or concerns about our governance structure, or any other matters, we’re happy to discuss.