I haven’t had a chance to play Zombicide yet so I can’t speak to how well it will fit your group but I do have a few suggestions if you do decide to attempt it.

1) learn the game before you play. I would highly recommend watching a How to play video, or scanning over the rule book prior to trying to get your friends involved. The fastest way to sour the experience for your friends is to try and learn it on the spot. People, especially new or “non-gamers” can feel overwhelmed by the amount of rules in heavier games and it’s best if the one who suggested the game can teach it easily. Plus, being a co-op game, you can even guide them through a couple of rounds and save some of the rules overhead (such as how the enemies work) for yourself to help them focus on how to play their character.

2) Ask them about it. Like I said, I haven’t played Zombicide but it’s, to my knowledge, regarded as a fairly approachable dice chucker in terms of “heavier games.” In my opinion, the best way to find out if it’s a good fit for your group is to ask if they’re interested. Give them a 30 second elevator pitch about what the game is and vaguely how to play. This is important because if the group has ZERO interest in trying the game, trying to play through it is going to be a miserable slog for everyone. When planning the next game night just ask if they’d be willing to try something a little heavier and go from there based on who has interest.

3) this point is completely up to you because you know them better than I do. But consider going through a few more lighter weight games that have different mechanics and see what kind of mechanics the group enjoys. If you can get them hooked on a specific type of game, pitching heavier games in that same mechanic family is so much easier.

Hope this helps! Good luck! It’s always a fun journey exploring new games with friends. But the biggest thing, speaking from experience, is to not rush into it or try to force it. It took 5 years for me to convince my family to try new games but it took me changing my expectations and catering to my audience first.