I'm learning the salsa vs. I've been learning the salsa

I'm learning the salsa.

The sentence tells us what you are doing at the present time, but perhaps not at this moment. eg.
I'm learning the salsa. I have a dance partner and we are taking classes twice a week.

I've been learning the salsa.

The sentence tells us that you started learning t

Well, when we use perfect tense, we say that the event started in the past and it's still going on. so far so good. But when I say I'm learning the salsa. I refer to these days. So It also started in the past. maybe my first class was 2 days ago...! I can not see any difference

There is not much difference. It is the idea that the speaker wants to convey - that the activity started in the past, or that it is happening right now.. The context becomes important:

eg.
I've been learning the salsa, and it's really made a big difference in my love life.
I am learning the salsa, hoping that it will make me more attractive to women.

Yeah, That answer has helped me a lot. Thank you so much