There is a clause in the CUSMA that requires the parties to complete a review after six years, at which point in time the parties will determine whether they want to extend the period of application of the agreement. Should they determine after six years that they do not want to formally extend the period of application of the agreement at that time, then the agreement would nevertheless remain in force until the 16-year anniversary, during which time the parties could discuss whatever topics they want.
On February 16th, 2023. See this statement in context.