California Code, Revenue and Taxation Code - RTC § 17209

(a) For each taxable year beginning on or after January 1, 2020, and before January 1, 2030, Section 280E of the Internal Revenue Code,  1 relating to expenditures in connection with the illegal sale of drugs, shall not apply to the carrying on of any trade or business that is commercial cannabis activity by a licensee.

(b) For purposes of this section, “commercial cannabis activity” and “licensee” shall have the same meanings as set forth in Division 10 (commencing with Section 26000) of the Business and Professions Code.

(c) This section shall remain in effect only until December 1, 2030, and as of that date is repealed.