What Should a New Player Expect?

I', watching Jynxi's stream for the first time and this game looks really fun, albeit somewhat intense. I grew up playing the original MW 1 and 2, but that's basically where I maxed out in the world of competitive shooters. Currently, the only "shooting" game I play is Fortnite, which I'm kind of over. What should someone with no previous Rainbow Six knowledge - like myself - expect when going to play this game for the first time? Is there a big learning curve?