To look at Jim Allison, you wouldn’t immediately think that he’s a Nobel Prize-winning immunologist. He looks more like a harmonica player, which he is, too. In fact, you can occasionally catch him onstage playing with his longtime friend, Willie Nelson. But as a new feature-length documentary reveals, Jim Allison is actually the reason why certain people with melanoma have their lives back. Narrated by Woody Harrelson, Jim Allison: Breakthrough features interviews with Allison’s family, professors, reporters, and colleagues, as well as a cancer patient who tried every kind of therapy without any success—until she tried Allison’s breakthrough drug, Ipilimumab.

Allison was born in 1948 and grew up in Texas, the son of a housewife and doctor. His two older brothers called him “diamond-head” for how hardheaded he was, referring to a trait that eventually served in Allison’s favor as a scientist. When not wandering in the woods playing his harmonica, Allison played with a chemistry set in his garage, with encouragement from his father—having lost his mother to lymphoma when he was only 11 years old.

Jim Allison looks at T cells/ Courtesy Malinda Allison

Allison graduated high school at the tender age of 16, heading to the University of Texas in Austin to study biology. It was in college where he learned the importance of perseverance and developed an interest in T cells, which are a central part of the body’s immune response, carrying receptors that have the ability to zero in on a diseased cell and vanquish it. As Michael Curran, Assistant Professor at the University of Texas MD Anderson Cancer Center, says in the film, “[Allison] was the first one to actually purify the molecule by which T cells recognize everything.”

In 1974, Allison moved to San Diego to learn more about the immune system at Scripps. That’s when he met Willie Nelson and brought him to a local dive bar to play live, developing a friendship with him that led to Allison occasionally playing harmonica in Nelson’s band.

Willie Nelson and Jim Allison in concert/ C3 Presents

Tyler Jacks, director of the Koch Institute for Cancer Research at MIT, says in the film, “Part of Jim’s success is that he’s an iconoclast. He doesn’t care. He doesn’t care that he’s not following convention. He’s following his own thoughts, his own motivations. He’s willing to do it in the face of his colleagues not necessarily believing him.”

Meanwhile, Allison successfully spoke against a Texas bill opposing the teaching of evolution in public schools and was offered a full professorship at Berkeley. He theorized that cancer cells highjack CTLA-4 protein receptors and trick T cells into stopping them from attacking tumors. The theory led to Allison developing his drug, Ipilimumab, or “Ipi,” as it came to be known. But watching the film, one question immediately comes to mind: Was it more difficult to actually develop the drug or to get it to people?

“I think getting it to people,” Allison tells High Times. “There was a lot of well-deserved skepticism. Nonetheless, at a certain point, that became irritating. I can argue the points of the science. If somebody says, ‘Here’s another explanation for what you’re telling me,’ I can buy that. What I can’t accept is somebody saying, ‘It’ll never work, just because.’ That just, to me, is unacceptable. And I went through a couple of years of that.”

Jim Allison winning the Nobel Prize in 2018/ Nobel Media AB

Allison says that many people in the scientific community had the idea that “immunologists were just a bunch of voodoo agents selling snake oil,” which raises another question: Can Allison identify with cannabis researchers who are struggling to fight longstanding stigma, not to mention prohibitive laws against marijuana?

“Yeah, in some ways I can,” he says. “I mean, these are, in a lot of ways, difficult times to live in, with people thinking everybody’s entitled to their own facts. But you’re not. Facts are facts and data is data. I would just tell people, develop the data. The answer’s in the data. Having said that, I will add that you can look at it a number of different ways. Once you’ve got the data, take a step back and say, ‘OK, well, what does this tell me? Because my experiment may be telling me something else. That data that popped out may be telling me something about a question I didn’t even ask here.’ And the only way to find that out is just to look at it and think about it and view it as sort of a crystal. You hold it up to the light and look at it—how it refracts, how it changes as you look at it. Just keep an open mind and don’t just get limited to the narrow channels that most of us are trained to go down.”

Jim Allison: Breakthrough is in theaters September 27.