Checkpoint inhibitors do not work well in cancers where there is no underlying immune response. One example of such a non-inflamed tumor is prostate cancer.

So a key question is how do we convert a non-inflamed tumor (where few T Cells present) into an inflamed one (T cells are plentiful and active)? 

In this latest episode, using prostate cancer as an example, Dr James Gulley from the National Cancer Institute (pictured below at ASCO 2015) talks about how therapeutic cancer vaccines may achieve this effect.

Dr James Gulley NCI

Giving a cancer vaccine first could make checkpoint inhibitors more effective.