SCHEDULE 13G 0001580115 XXXXXXXX LIVE Common Stock, $0.0001 par value per share 07/25/2025 0001806952 Lyell Immunopharma, Inc. 55083R203 201 Haskins Way, South San Francisco CA 94080 Rule 13d-1(c) Gates Frontier, LLC WA 1040964.00 0.00 1040964.00 0.00 1040964.00 N 5.6 OO For purposes of Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), all shares of the Common Stock, $0.0001 par value per share (the "Common Stock"), of Lyell Immunopharma, Inc. (the "Issuer") held by Gates Frontier, LLC ("Frontier") may be deemed to be beneficially owned by William H. Gates III as the sole member of Frontier. Item 11 is based on 14,808,006 shares of Common Stock outstanding as of May 30, 2025, as reported on the Issuer's Form S-3 filed on July 18, 2025, plus 3,753,752 shares of Common Stock issued by the Issuer on July 25, 2025, as reported on the Issuer's Form 8-K filed on July 25, 2025. William H. Gates III X1 1040964.00 0.00 1040964.00 0.00 1040964.00 N 5.6 IN For purposes of Rule 13d-3 under the Exchange Act, all shares of the Common Stock of the Issuer held by Frontier may be deemed to be beneficially owned by William H. Gates III as the sole member of Frontier. Item 11 is based on 14,808,006 shares of Common Stock outstanding as of May 30, 2025, as reported on the Issuer's Form S-3 filed on July 18, 2025, plus 3,753,752 shares of Common Stock issued by the Issuer on July 25, 2025, as reported on the Issuer's Form 8-K filed on July 25, 2025. Lyell Immunopharma, Inc. 201 Haskins Way South San Francisco, CA, 94080 Gates Frontier, LLC ("Frontier") and William H. Gates III ("WHG") Frontier - 2365 Carillon Point, Kirkland, Washington 98033 WHG - 500 Fifth Avenue North, Seattle, Washington 98109 Frontier is a limited liability company organized under the laws of the State of Washington. WHG is a citizen of the United States of America. Y See the responses to Item 9 on the attached cover pages. See the responses to Item 11 on the attached cover pages. See the responses to Item 5 on the attached cover pages. See the responses to Item 6 on the attached cover pages. See the responses to Item 7 on the attached cover pages. See the responses to Item 8 on the attached cover pages. Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit 1: Joint Filing Agreement by and between Gates Frontier, LLC and William H. Gates III Gates Frontier, LLC /s/ Alan Heuberger 08/01/2025 William H. Gates III /s/ Alan Heuberger 08/01/2025 Duly authorized under Special Limited Power of Attorney appointing Alan Heuberger attorney-in-fact, dated October 11, 2013, by and on behalf of Michael Larson, filed as Exhibit 99.2 to Gates Frontier, LLC's Schedule 13G with respect to KiOR, Inc. on October 31, 2013, SEC File No. 005-86313, and incorporated by reference herein. Duly authorized under Special Limited Power of Attorney appointing Alan Heuberger attorney-in-fact, dated August 12, 2008, by and on behalf of William H. Gates III, filed as Exhibit 99.3 to Gates Frontier, LLC's Schedule 13G with respect to KiOR, Inc. on October 31, 2013, SEC File No. 005-86313, and incorporated by reference herein.