Ich gehe ins Kino or Zum Kino
Ich gehe ins Kino. ( in + das = ins because of akkusativ )
Gehst du zum Kino? ( zu + dem = zum because of dativ)
How the same sentence akkusativ is changing to dativ when we are asking as question?
It is not about asking a question. You would also say
Gehe ich ins Kino?
Du gehst zum Kino.
In combination with "Kino" "in" and "zu" do not mean the same thing. "Ich gehe ins Kino" means you are going to the movies, "Ich gehe zum Kino" means you are going to the movie theater (to the building, not necessarily inside).
"IN" can take accusative or dative - in this case accusative due to motion. "ZU" always takes the dative.