Assume you’re life-lusted and are willing to abandon every moral you have just to live. Paying for cancer treatment is also worth prison time to you.
Also assume you’ve exhausted all ethical fundraising options, i.e. GoFundMe, loans, etc. and that insurance won’t cover treatment for whatever reason.
From the usa, safest bet would probably be a heist on an armored vehicle, killing the driver and taking his clothes and belongings and heading to mexico to change the money and get healthcare.
Or better yet , you might not even need to kill the driver. impersonate or bribe a cop and just pull them over and take the money. Cops did that all the time a few years ago, targeting companies related to weed since its federally illegal, making the transport of the profit on interstate highways vaguely illegal. They still can, but they supposedly dont.