According to a news release uploaded earlier by Samsung on their Mobile Press website, the PlayGalaxy Link app is planned to be released on the new Galaxy Fold, Galaxy S9, S9 Plus, Galaxy Note 9, and Galaxy A90 in early December this year. The PC streaming app was previously released on the Samsung Galaxy S10 series earlier in November as well. On a side note, Samsung stated that the official PlayGalaxy Link game controller shown in the top image can only be purchased in the USA and South Korea through the Samsung Mobile Accessory Partnership Program. With that said, the controller is not a mandatory requirement, as you could still use the application with most Bluetooth gamepads that are compatible with Android phones.
PlayGalaxy Link beta testing for the aforementioned smartphones is currently available in South Korea, US, UK, Canada, Italy, the Netherlands, France, Singapore, and Russia. More information on Samsung’s PC streaming app can be found on its official website. (Source: Samsung via XDA)