UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 Arcus Biosciences, Inc. (Exact name of Registrant as specified in its Charter) (State or other jurisdiction of incorporation or organization) Delaware 47-3898435 (I.R.S. Employer Identification No.) 3928 Point Eden Way Hayward, CA 94545 (Address of principal executive offices) Registrant ...