X0508 4 2026-02-09 0001806952 Lyell Immunopharma, Inc. LYEL 0001327111 Seely Lynn C/O LYELL IMMUNOPHARMA, INC. 201 HASKINS WAY SOUTH SAN FRANCISCO CA 94080 true true false false President and CEO 0 Common Stock 2026-02-09 4 A 0 20000 0 A 82159 D Common Stock 2026-02-10 4 S 0 438 23.12 D 81721 D Option (right to buy) 23.71 2026-02-10 4 A 0 155000 0 A 2036-02-09 Common Stock 155000 155000 D Pursuant to performance-based restricted stock units granted to the reporting person on February 9, 2024, 20,000 shares were issued on the Transaction Date upon the achievement of certain performance criteria certified by the compensation committee of the Issuer's board of directors on the Transaction Date. Shares automatically sold to cover tax withholding obligation from settlement of vested restricted stock units. Twelve and one-half percent (12.5%) of the total number of shares of Common Stock subject to the option will be vested and exercisable on the date that is six (6) months after February 9, 2026 (the "Vesting Commencement Date") and thereafter, an additional one forty-eighth (1/48th) of the shares will become vested and exercisable monthly on the same day as the Vesting Commencement Date (or, if there is no such corresponding day for a given month, on the last day of such month), until the option has become vested and exercisable with respect to one hundred percent (100%) of the shares, subject to the Reporting Person providing service to the Issuer through each applicable vesting date. /s/ Mark Meltz, Attorney-in-Fact 2026-02-11