The Ver. 4.020 update slated for release on Wednesday, February 27, 2019 implements design changes to improve operation stability for DirectInput USB controllers used with the Steam version of the game.
If your controller (primarily PlayStation®4 controllers, arcade sticks, etc.) employs DirectInput, launching STREET FIGHTER V after applying the above update will result in the loss of controller functionality.
After installing the 4.020 update, please adjust your settings as per the instructions below in order to resolve the issue.
*Please note that Xinput controllers (Xbox 360 controllers, Xbox One controllers, etc.) do not experience this issue.