This is absolutely a scam. The easiest way to tell is to ask why they would involve a total stranger as a 50% partner rather than keep all the money to themselves. What value do you bring to the table?
Answers:
1) They are engaged in criminal activity and using you to launder money. You are the one law enforcement will likely arrest leaving them anonymous. This option is pretty unlikely.
2) The will deposit the money somehow, in a way that will take a while to be detected as fraud (fake cashier's check, etc.). It will be just long enough for you to send them the $2,000 and run off with it before the bank reverses their deposit and leaves you in a hole and possibly trouble with the law for depositing fake checks. Semi-Likely
3) They will use your bank card to buy a bunch of stuff and never call you back or deposit any money. Or possibly they will do a deposit that will bounce. Most likely.
The fact that this is a scam is painfully obvious. Unfortunately these things often work because people's greed overpowers their common sense.