One of the most common idiomatic phrases in Polish is chodzi o ... or some variation. Phrases like this are called "discourse markers." They don't give us new information; instead, they give us cues and clues as to where the speaker is going with his speech--for instance, what the subject is, or what we should pay special attention to.
I have had elementary level students who tried to translate the Polish phrase directly into English:
To chodzi o obiad -----> It walks about dinner.
As with most idioms, translation is not the best solution. There are many better ways to translate the various forms of this expression. Here are a few of them:
To chodzi o X It's a question of X OR It's about X
OR I mean X OR I'm talking about X
Chodzi mi o X (same as above)
O co chodzi? What's it all about?
Jeśli chodzi o X ... If it's a question [matter] of X OR If it's about X OR If you mean X
Nie o to chodzi It's not about that OR That's not what I'm talking about
OR That's not what I mean OR It's not a question of that.
Wiesz o co chodzi You know what I mean OR You know what I'm talking about
Here's a short dialog that shows how some of these are used in English:
She: I need to talk to you.
He: Okay. What about?
She: I'm tired of your games.
He: What are you talking about? If it's a question of golf, I'll never give it up.
She: It's not about golf. I'm talking about us. You know what I mean.
He: If you're talking about my secretary, there's nothing going on ...
She: It's not a question of something "going on." It's about honesty.