Poland have very rich history with Scandinavia in early middle ages. Especially Dennmark. Polish pirates (and later corsairs) Chąśnicy ,called by Skandinavians “Vindafrelsi” were very agressive towards Danes, so agressive that they actually exterminated 1/3 of all Danes and we speak only about pirate raids not the wars. Also Danes were one of the two main enemies of Obodrites and Wagrians. There were pirate raids on Norway (read about Konungahela). There were vikings living and serving under Polish king (read about Jomsborg/Wolin). After some time actually most of those vikings were Slavs ,and Harald Bluetooth was attacking Norway with his Slavonic vikings.
Kings of Dennmark ,Sweden and Norway of that period were half Polish and were grandchildren of Polish prince Mieszko I. Familly ties were quite visible through the relations between cousins. Son of Mieszko I ,Bolesław the Brave was called by his skandinavian relatives “Burisleif”.
Archeologists find Slavic settlements even on Iceland. Actually it is suspected that a person mentioned in one of the sagas ,a man with his slaves living on Iceland before first Norwegians came there ,was actually a Slav ,because signs of Slavonic presence on Iceland are very old.
Also when you look at the genetical maps ,you may clearely see that there are parts of Scandinavia (for example Norway) where R1a haplogroup is very significant. There is quite few similarities in culture because Slavs had strong cultural and economical relations with them. Scandinavian languages also have some linguistic influences.
If you would read in Polish ,you would have quite many materials on the subject. Maybe I’ll translate some stuff and put it on my thread about translations.
If it comes to looks I wouldnt be so much into it. Western and most southern Slavs look similar because of the skull shapes and traits (like you or me) but we are much more beautiful.