To explain some of this to lay readers. Cancers are weird. Everything from the shape and structure of them to how they get and structure the blood supply system. This paper and its subfield focus on the local immune environment of cancers.

Cancers somehow avoid being killed off by the immune system. Why the immune is not working on the cancer is a big question.

One thing being tried with this vaccine approach is teaching the immune system hey this actually is cancer.

This paper has for IV given vaccines, the immune system is working two ways to fight cancer. The innate immune system is working in the local tumor environment. T cells are boosted and fight the cancer better.

This study was done in mice, so don't get hopes up too much. How much different between lab mice tumors and a particular human cancer is a big question.

Cancer is better understood as a collection of diseases. The genotype of the cancer, the location, and tissue of origin all matter. Not all cancers are as scary as others. Don't panic if you here the c word. Find out what it is more in depth before worrying too much. Stressing yourself out wouldn't help.