Hi,

In Italian, personal pronouns aren't obligatory as in English, you can safely omit them if the subject is clear, but you use them for emphasis. So for example:
"Vieni al cinema stasera?", "Sì, vengo"
"Chi viene al cinema stasera?", "Io vengo"
In the second example the subjects uses "Io" to distinguish himself.

Ciao,
Massimo.

With a question like: chi mi aiuta col trasloco sabato?

The answer often would be: vengo io!

It is present also if would be correct the future: verrò io

Moreover in Italian language often the subject is not written, and when you see it like in this situation it gives a stronger meaning to the answer

The purpose of saying "vengo io" instead of just "vengo" or "io" is to give more emphasis on the fact that it's me the one who comes. 

Ha senso. Grazie!