There have been many instances of stealing coins but no one have ever hacked the Bitcoin, these thefts has just been lack of the precaution by the owners, some problems with two-way authentication and other similar issues. No one can hack Bitcoin thanks to advanced blockchain technology. Every block is linked to another block, so basically if you want to alter some transaction there must be approval from the individual within the block and every transaction that followed it.
Blockchain has been mainly developed for the Bitcoin network, because in the past there were several tries to create cryptocurrency but there were no mechanism that would stop double spending (situation when people are spending their assets more than once). Blockchain was the first technology that overcame this problem since your private key that lead you to your cryptocurrency is not enough to allow spending. Also, this technology seems to be useful in other field of technology and other cryptocurrency as well, not only Bitcoin.
As we already said, there must be a consensus from the large number of people within a block to validate transaction, so if hacker want to hack a person, he must hack an entire network and all of the assets owned by many people within the block. Of course there are some negative sides of the blockchain technology especially when it comes to the Bitcoin. In comparison to some other cryptocurrencies Bitcoin has really high transaction time and block time also. For example Ethereum, there is a big difference in transaction times and block times.
To make a resume, there is no way to get your cryptocurrency stolen by hackers. Recommendation is to keep you coins in hardware wallet, keep your private key to yourself and don\'t leave your coins on the exchange.