On 12 August 2020, the official release date for the third movie of the Gintama series: Gintama THE FINAL movie was announced. The film will be released on 8 January 2021. The upcoming movie will be directed by Chizuru Miyawaki. A new trailer for the said film has also been revealed.
You can watch the new trailer here.
Source: Gintama THE FINAL Official Website