You are correct, it is not usually recognized for Keytruda. The critieria that it can work is met with information from the GI oncologist at Oregon Health and Science University, OHSU, Portland, OR, where my husband had his surgery and the chemo. The pathology reports were reviewed and found that his tumors remarkably and unusually filled the critieria that had to be met to use Keytruda. My husband had many many mutations. That is the best I can explain it. The high number of mutations of a certain kind coincided with what Keytruda, an immunotherapy drug, was capable of zapping the cancer from his adrenal glands where it had metastasied to 6 months after the major surgery. Chemo wasn't working so they went back to the drawing board and reviewed all that was available on my husband's tumors and found he met the critieria. For him it brought back his quality of life, although we still of course have to deal with the digestive and immunity effects of the surgical removal of his organs with the tumors attached. The research is always moving forward. I appreciated President Biden's push for the interventions for cancer. Interventions are moving forward. The following article explains the mutations critieria for use of Keytruda, but is talking about lung cancer, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7920921/ The next post is about use of pancreatic cancer and immunotherapy. https://www.cancer.org/cancer/types/pancreatic-cancer/treating/immunotherapy.html
There are likely some research papers on PubMed on the most recent developments in the use of it.But the cancer. org article gives more critieria, specific to Pancreatic cancer. Hope! for your search for successful interventions.