So I emailed the support and received this instant automated reply:

Hello,

First of all, we want to thank you and all the Pandemic players for your loyalty and support over time. Unfortunately, we are taking the Pandemic app off the stores. We have worked hard over 4 years on Pandemic and withdrawing it from the stores has not been an easy choice. This decision was made with a heavy heart for a multitude of reasons that we cannot disclose.

For now, only PC, App Store & Google Play has been removed. Microsoft version will follow Jan 31th 2022 and then Nintendo Switch by the end of July 2022.

Regarding the game, as long as it has been purchased and downloaded prior to removal from the store, then you will continue to have access to the game. If you do uninstall the game, you will need to access your library to locate and install the game again.

We appreciate your continued support all this time. Thank you for your understanding,

Best regards, Asmodee Digital Support

On the steam page:

Notice: At the request of the publisher, Pandemic: The Board Game is no longer available for sale on Steam.

The game isn't listed on Asmodee's site neither.

That's sad. Hopefully they never remove Terraforming Mars or Carcassonne.