As Coley’s Toxin proved, anything that generates a significant immune response can act against cancers, probably as a consequence of nonspecific inflammation. That is not so much to do with “measles” as such, as that our immune systems are designed to recognize bad shit and react with all guns blazing upon detection. Measles is bad shit, hence… The catch is that said “all guns blazing” response inevitably has severe consequences for the owner of said immune system, so more controlled methods are being developed. This is the theory behind the development of checkpoint inhibitors, which are exceptionally promising therapies, but similarly not without side effects. If you unleash the immune system beyond a certain point, the results are sort of like nuking your own country to defeat an invading force. You may kill all the enemy, but your own will not fair so well either.
ETA: Ran this past my brother, who is a cancer researcher, and he added this: “You’ll see regression of any hematological malignancy following any major infection due to spontaneous release of IL-2. Cooley showed that in 1890. Doesn’t make major infections a good treatment option.”
