I think Chun-Li is the superior martial artist, with greater control of Ki, great agility, speed and strength, especially in her legendary legs. Cammy is also immenselly skilled but she seems to be trained more in assassination and military techniques than martial arts and she's quite inferior when it comes to the control of Ki, she has great athleticism, great agility, speed and reflexes that rival and may even surpass Chun-Li's, but is far behind in terms of strength. Chun-Li has her Ki and superior power in her legs to her advantage, Cammy has her athleticism...

In my mind, it seems clear to me that Chun-Li would win.