As comedian Brian Regan famously noted, cranberry juice does seem to be added to everything these days. There's cran-apple juice, cran-grape juice, and even cran-strawberry juice.

That's how it's starting to seem with Incyte Pharmaceuticals (INCY 0.77%) and its immuno-oncology drug INCB24360 lately. In February, the biotech agreed to test INCB24360 in conjunction with Merck's PD-1 inhibitor MK-3475. In mid May, the biotech committed to test the drug with AstraZeneca's PD-L1 inhibitor MEDI4736. And earlier this week, Incyte signed yet another agreement to test INCB24360 with another immuno-oncology drug, this time with Bristol-Myers Squibb (BMY 1.25%) and its nivolumab.

Quite a bit of dealmaking there. So what's behind it?

In the video below, from Market Checkup, the Motley Fool's health care-focused investing show, health care analysts Michael Douglass and David Williamson lay out the deal and why so many companies want this drug added to their immuno-oncology arsenal.