Developers Plague Inc: Evolved kept their promise and released a free DLC for the PC version of the game. The add-on allows you to look at the usual gameplay from a slightly different angle.
In Plague Inc: The Cure, gamers will lead several research teams that are trying to take control of the global pandemic. Scientists will have to stop disease outbreaks through social and economic programs and ultimately find a vaccine.
You can download the DLC absolutely free from the game page on Steam. According to the developers, the add-on will be free until the COVID-19 pandemic is brought under control.