At 10 million °C, nothing much. Increase the temperature to about 14 million °C, though, and the hydrogen will start to fuse to become helium. This generates so much energy that, depending on what is doing the squeezing, the resulting cloud may not be able to contain itself and expand explosively. (e.g., if it is gravity doing the squeezing, then what you get is a star, but if it's another explosion doing the squeezing, then it's a hydrogen bomb).

What a specific question! I have to start this answer with a disclaimer: I do not consider myself an expert in high-pressure, high-temperature systems. These conditions are so far from anything we deal with on a daily basis that the intuition of a typical scientist could easily be wrong. I have an idea of where you would go to find an expert: an astrophysicist would know the chemistry of stars, which likely contain the exact system you are asking about, or even a geophysicist (that studies the high-temperature, high-pressure conditions in the center of the earth) might know. If you need a definitive answer, I would consult someone that spends their whole career working in such an area. As a non-expert, I offer my educated guess. Assuming the hydrogen and helium is squeezed together to a high enough pressure, the conditions probably match those of a star, so you might create a star. But the temperature and pressure you would need to do that is probably unrealistic to achieve.