Present Continuous for future arrangements

Arrangement (plan o disposición)
 

Positive	I'm seeing a film tonight. We're having dinner at their house tomorrow.
Negative	She isn't leaving until Friday. They aren't coming to the party.
Question	What are you doing this evening? Is she meeting us at the cinema?

You can use the present continuous for future arrangements which we have planned for a fixed time or place.
Don't use the present simple for this (future arrangements). I see some friends tonight.
The present continuous is specially common with the expressions tonight, this weekend, etc., and with these verbs: go, come, meet, leave, see and arrive.