Before I start going off the deep end with my pursuit of a magical clinical trial, let me break down immunotherapy and immunotherapy combination trials to a 4th grade level. Or better yet, in terms of Star Wars, since this is how I explained it to the kids. This is how I explain most things to my kids.
As Merrick (my almost 5th grader) will gladly tell you, cancer is just a bunch of normal cells gone bad. Sounds like the Republic, huh? Cells have an off switch and know when to stop growing, unless the pull of the Dark Side is too great. This is the case for cancer cells. A switch has been flipped and they continue to grow until they have taken over the galaxy.
Normally your immune system (the Rebellion) would see these cells growing when they shouldn't be, and rush in to destroy them. But like the Republic, cancer is a stealthy bastard and uses a force field to make it invisible to your immune system (the Rebellion). Immunotherapy works by sneaking on board a Star Destroyer and deactivating the force field, enabling the Rebellion to see it, and sending in X-Wing Fighters to destroy it.
Immunotherapy breaks down cancer's ability to hide from the immune system, the immune system sees it, recognizes it as a foreign invader, and attacks and kills it like it's perfectly capable of doing.
In my world of colorectal cancer there are two types of tumors: MSI and MSS. In keeping with the 4th grade level here, I'm not going to explain the two, other than to say that roughly 10-15% of colorectal cancer patients have MSI tumors - which have responded well to immunotherapy trials. The rest of us schmucks have MSS tumors, and we don't respond to immunotherapy alone.
Enter a combination therapy. The general idea behind combination therapy is the immunotherapy gets the Republic to drop its force field, and allows the Rebellion/chemo/cancer drugs to do their job far more effectively with far less work.
At this point I'm awaiting a combination clinical therapy trial to open up. They're out there, just not at one of the two National Cancer Institute cancer centers in my backyard (University of Minnesota or Mayo Clinic). While I wait, I shall sit on an oral chemotherapy called Lonsurf. It's not meant to shrink my sexy lung mets, only keep them stable while I bide my time.