Well, officially it is Finnish-German production, but most of performers come from Finland and most events take place there as well (more precisely, in Lapland near the Artic Circle), so you get, above all, a picture how life in those harsh conditions go on and what potential dangers and risks can appear.
If/when some virus is included, then it is always "food for thought", but in the modern fast developing technology - you never know; what was unimaginable a decade ago, can be a reality now, etc. All in all, as "pure crime stuff" was included, I had nothing against this inclusion (usually I am not into non-human death inducers).
As for the cast, all main performers were unknown to me, but there was a strong and nice team-work, no character "shining" above or at the expense of others. It is more to my liking than the use of same actors-actresses in similar series, causing confusion or reducing the thrill if they tend to play similar roles as well.
Based on the ending scenes, I am looking forward to the potential Season 2.
PS I have to admit that I liked Seasons 2 and 3 even more - perhaps due to more versatility and other degradation factors than virus. The inclusion of more international performers has also broadened approach and geography. And, well, it was okay to watch snow and blizzard if there is over +20 degrees Centigrade outside... :)