Suffering, cause of suffering or accumulation, ending of suffering and path or way are know as the Four Noble Truth. This is the first Buddha's teaching that Shakyamuni preached to the Five Bhikshus after His Enlightenment. Four Noble Truth is the theory abided by the Sound-hearing Arhat.
For suffering, there are the Three Sufferings, the Eight Sufferings which are the effects of Karma of sentient beings.
For accumulation, it is the causing of suffering. Accumulation means the accumulated Karma incurred by the Three Poisons, that is, desire, anger and illusion.
For end of suffering, it is the effect of cultivating the Way to attain the state of Nirvana.
For path or way, it is the method or the cause to end suffering, that is, to practice and cultivate the Way.
Again, in emptiness, there is no suffering, no cause of suffering, no ending of suffering and no path, because the reality character of the Four Noble Truth, one of the important Buddhist Dharma, is also empty.