It is rather inconclusive at this time, pending further research and inquiries.
Most regulations and laws seem to refer to actual gambling where, often, you have real money or assets involved or have the intent to profit via real money and assets either directly or potentially through some grey market.
The only argument I can see here now is taking "online gambling" literally because that, assuming we have gambling and coop in the game, you could say "Well you are a) doing something that could be dubbed as gambling and b) doing so with a computer and over an online connection, so it's technically online gambling".
But if no real money is involved, I consider it a moot point and I question whether real authorities would feel a need to regulate here. Other criticisms (including over controversial loot boxes in Overwatch, BF II, etc.) I've seen is the "think of the children" factor where it is questioned if such mechanics could encourage such vices and addictions.
Even if we consider the mere act of simulating real gambling activities as "special", just like certain nudity or excessive gore would require regulation or restrictions in movies, works of art, games, etc.: CP2077 would surely aim for or get a mature tag, an "adults only" rating, so minors should (on paper anyway) not play the game anyway and thus not get in contact with such contents including gambling simulations, unlike BF II or Overwatch that have milder ratings (lootbox debate).
My view summarized: Long story short, you being able to gamble in the game is fine, it likely gets a mature (18+) rating. Being able to do so in a COOP setting should be fine either if the "real money involved aspect" is not covered at all, respective laws should not be applicable there in my view or, all in all, consider it a non-issue due to the rating if "think of the children" plays a role. And even if CDPR through their lawyers and so on deem it "potentially or actually tricky": Just turn it off for COOP then if it actually would be some sort of issue.
I still expect gambling related activities in general for the game. Just like you had in Fallout: New Vegas.