Ich gehe mit meinem Freund ins Kino.
English: I go to the cinema with my friend.
In German, some prepositions always require the following noun or pronoun to be in the dative case. These are called 'prepositions with dative'.
You use these prepositions when talking about origin, location, time, possession, direction (to a person or place), or with certain verbs. The noun or pronoun after these prepositions must be in the dative case.
Ich gehe mit meinem Freund ins Kino.
English: I go to the cinema with my friend.
Wir wohnen bei meinen Eltern.
English: We live with my parents.
Sie kommt aus der Schweiz.
English: She comes from Switzerland.
Das Geschenk ist von meiner Schwester.
English: The present is from my sister.
Ich fahre zu dem Bahnhof.
English: I go to the train station.