If you close your Coinbase account, any remaining balance in your account will be sent to the bank account that is linked to your Coinbase account. If you do not have a bank account linked to your Coinbase account, you will need to contact customer support to have your remaining balance sent to you via check.
If you have made any recent transactions on your Coinbase account, those transactions may not be processed until after your account is closed. For this reason, it is recommended that you wait until all of your transactions have been processed before closing your Coinbase account.
Once your Coinbase account is closed, you will no longer be able to access it. This means that you will not be able to view your transaction history or cancel any pending transactions.
If you have any questions about what will happen to your data after closing your Coinbase account, you should contact customer support.