what would happen in that case
do the minner will mine an empty block.
all the transactions will get cancelled
It's up to the miner (or most likely, his software) to decide. The miner can mine empty blocks if he chooses to but then he doesn't get any gas from transactions. The system is balanced in a way (or at least should be) that it's more profitable to include transactions in blocks than to mine empty blocks.
If the miner does not include transactions in the transaction pool in their block, nothing special happens to the transactions. If this miner wins the block the transactions simply stay in the pool until someone includes them in a block. If someone else wins the block he has probably includes some of the transactions in the block.