Some context. One of the drugs in the combination Ipillimumab has been used for a while now, and seems to produce long term survival in about 10% of patients with incurable melanoma. Some of these patients seem effectively cured, having survived 7 years or more without any other treatment. It seems likely that combination therapy will produce a better rate of effective cure. This is a pretty big deal, because advanced melanoma is otherwise a disastrous cancer to have.

Cost effectiveness... well ipillimumab costs 100k a year for 4 doses, and nivolumab is probably going to cost another 100k at least on top of that, and is generally continued indefinitely, and the medication to turn off overly vigorous immune responses can also be expensive...

But this is modern medical science how it should be. These are incredible, life changing drugs. The hype is justified. They are already spreading through many different types of cancer: lung, renal cancer, liver cancer, some breast cancer, some colon cancers. Toxicity is an issue, but this is generally temporary, and the quality of life tradeoff is different when there is the possibility of making the next 7 christmases. Furthermore, you have to balance the toxicity with the symptoms from progressive cancer or old style ineffective chemotherapy.