Why are there Chechens in Afghanistan?

Chechens are Muslim Sunnis, and they are very militant, especially like to fight mountain wars and guerrilla warfare. If you have seen the Russian film The Ninth Company, Afghanistan has many complicated ethnic and religious elements. Besides, Afghanistan is now occupied by western countries, so it is natural for Muslim brothers to fight together. Muslims believe that fighting pagans to death will send them to heaven. . . . Speaking of the Chechen war, there are black Muslims in North Africa among Chechen rebels. . .