Both are the same, they are the flagship phone of Samsung. The Galaxy S8 is a premium phone same as the Note 8. It's just that the Note 8 has a pen/stylus which you can use for navigating the device, writing messages, making notes, and even illustrations. Between the two I preferred the Note 8. It is great but expensive though.
Samsung Note 8 and Samsung Galaxy S8 are almost the same but there are some minor difference. Obviously, the Samsung S8 has its very rounded phones unlike Samsung Note 8 which is a lot straighter with less curve. Samsung Note 8 also has S-pen that works better for note taking. About their camera, I like the quality of Samsung Note 8 than the Galaxy S8 because when I tried both phones, Galaxy S8 has its very obvious filter which it changes the shape of your face and your complexion.