In August of 2017 it was announced that a new Knight Rider movie was in production with John Cena and Kevin Hart.
The Screen Rant article says that John Cena and Kevin Hart were being "targeted" for roles in the movie, implying that they hadn't actually been signed to the reboot at the time of the reporting.
That same article says the Justin Lin streaming series hadn't gotten off the ground.
Whether or not John Cena and Kevin Hart were actually interested in doing the funny Knight Rider reboot, (ala 21 Jump Street), the major tripping point for this movie project was that it was coming from The Weinstein Company. This news was announced in August of 2017. By October of 2017 Harvey Weinstein had been fired from his company. In February of 2018 The Weinstein Company declared bankruptcy and was completely defunct in July of 2018.
No writers, producers, or directors were named for the project in the article.
There's no reason to think this project will ever happen.
Chris Pratt & Danny McBride[]
According to a 2014 Screen Rant article, The Weinstein Company was trying to get Chris Pratt and Danny McBride to star in a previous version of the project, still on the comedy side. Brad Copeland (Arrested Development) was listed as a writer.