Samsung is working on a Portrait Mode for the single camera Galaxy S8 and the feature could possibly land through a future software update.
A customer inquired if such a feature is inbound and the resulting slightly answer from Samsung Electronics support read: "there is no information yet, but we hope that you will get portrait mode update with the next SW". Normally support responses would have only contained the first part, but this one not only suggested that the feature is a possibility, but also gave hope that it's just around the corner.
The Samsung Galaxy S8 lacks a dedicated telephoto camera like the Galaxy Note8 but could achieve fake background blur through the use of software, like on the Google Pixel 2 and 2 XL. And if it gets it, chances are its bigger brother, the Galaxy S8+ will also benefit from it.
Thanks, Sabith Pulukkool!