1.no matter who只能引导让步状语从句,这个从句充当主句的状语,且who在从句中也必须充当一定成分,如主语/宾语等,who后面必须使用陈述句序.
如：No matter who you are,you must obey the rules.
不管/无论你是谁,你都必须遵守规则.
2.而whoever有两种用法.
1）whoever = no matter who,也引导让步状语从句,此时两者没有任何区别.
如：No matter who you are,you must obey the rules.
= Whoever you are,you must obey the rules.
2）whoever还可以引导名词性从句,包括主语从句/宾语从句/表语从句/同位语从句.
该从句在主句中分别充当主语/宾语/表语/同位语,且whoever在从句中也必须充当一定的成分,如主语/宾语等.
此时,whoever不能用no matte who来换用,但是可做如下理whoever = anybody/anyone who.
如：(Whoever breaks the law) must be punished.
= Anybody/Anyone (who breaks the law) must be punished.
任何违反法律的人都必须受到惩罚.
其中,whoever breaks the law在主句中充当主语,为主语从句.
whoever在主语从句中也充当主语.