[Finished] The Witcher 3: Wild Hunt [Jigi] - Ends 5am GMT 30th - Lvl 3+

No it shouldn't spoil the games. The games are a non-cannon 'sequel' to the books, the tv series is an adaptation to the books so its completely fine to watch it without playing the games, actually I would recommend it :)

I haven't played the games. From what I've read online, the TV series covers the events in the original books. The games are set some years after the books, where Geralt can't remember the events of the novels.

Hm.... I guess the answer is mostly "no". As far as I could tell, all the episodes in Season 1 happen quite some time before the events in the games... And, also, there is no guarantee that show and games follow the same exact story anyway.

Now, to be picky, watching the show will make you know some of these characters beforehand, so I guess this will alter your perceptions of the characters a little in the games (like, had I seen the show, I would trust some people in the game right off the bat). But I think such alterations are so minor, I would still say "no spoiling".

Now, the other way round: the game spoils many things of the show! Since I saw many characters in the games much later in the timeline, I had expectations about their survival.... But again, it might not be exactly the same story!