In the recent April Lineup announcement post for PlayStation Now, three games will be available for all PlayStation Now subscribers starting tomorrow, April 6th.
The games mentioned are Marvel's Avengers, Borderlands 3, and The Long Dark.
Marvel's Avengers will be available to play until July 5th, 2021. At this point, the game will be removed from the service. Borderlands 3 will be available until September 29th, 2021. As the same with Marvel's Avengers, at that time, the game will become unavailable to play through PlayStation Now.
The Long Dark does not have an unavailable date, so it is assumed that you will be able to play the game until they decide to change this.
PlayStation Now Trial
Sony has also announced that starting Wednesday, April 7th, those who do not have a valid PlayStation Now subscription will be able to sign up for a seven-day free trial.
This trial is only available for Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Japan, Luxembourg, Norway, Portugal, Spain, Sweden, Switzerland, The Netherlands, UK, and the USA.