Michigan Compiled Laws, Chapter 257. Motor Vehicles § 257.312k

(a) A commercial driver license that expires on or after March 1, 2020 is valid until March 31, 2021.A commercial driver license that expires after March 31, 2021 but before August 1, 2021 is valid until 120 days after the date of the expiration.

(b) Medical certification for operator's or chauffeur's license holders with a group designation required under 49 CFR 391.45 that expires on or after March 1, 2020 is valid until March 31, 2021.Medical certification for operator's or chauffeur's license holders with a group designation required under 49 CFR 391.45 that expires after March 31, 2021 but before August 1, 2021 is valid until 120 days after the date of the expiration. This subdivision does not apply to either of the following:

(c) Hazardous material endorsements that expire on or after March 1, 2020 are valid until October 29, 2020. A security threat assessment required under 49 CFR 1572.13(a) that is valid on or after March 1, 2020 is valid until October 29, 2020. An individual with a hazardous material endorsement that is extended for 180 days under this subdivision must initiate a security threat assessment with the National Highway Traffic Safety Administration at least 60 days before the expiration of the hazardous material endorsement.