Samsung Electronics is currently working on a future update that would see the Galaxy S8 single camera support portrait mode. Presently, Samsung Galaxy S8 does not have a telephoto camera like the Galaxy Note8 but it can produce blur background using a software, just as it is on Google Pixel 2 and 2 XL.
A user (Sabith Pulukkool) asked if Samsung Galaxy S8 will get portrait mode update similar to Google Pixel 2 and Samsung Electronics replied
“…unfortunately there is no information yet, but we hope that you will get portrait mode update with the next SW”.
This response from the South Korean manufacturing giant is not usual because support responses are normally obscure. However, this response did not only give hopes that the feature will be coming, it also specified the next update.