In Method acting actors along with facial expressions, tries to change their antics, dialogue delivery for adding more depth in the acting, they try to completely transform themselves into the character. Before this technique, Stanislavski's system was more popular, which is considered first technique for method acting, today it is considered as natural acting. Where primary focus was on facial expressions which looks natural.
Here actor can keep himself in a situation, due to which real emotions can come on his face, for example in a movie scene an actor have to cry, here actor can remember something which make him very sad and their is a possibility of having real crying facial expressions.
In some cases a trained actor who have good control over his facial muscles can make expressions according to his understanding about facial expressions occur in a human face for different emotions.
The ultimate aim of Stanislavski's system of acting is bringing facial expressions which looks natural.
The best example is ifran khan acting
Ifran khan tries to give perfect facial expressions, he is a trained actor and have understanding what type of facial expressions is required for different types of emotions. Never tries to show variations in antics or dialogue delivery.
Other examples are
Mohanlal from Driyshum
Amir khan from taare zameen par
Sharukhan from swadesh
Danush from puthupetai
Surya from soorari potru
Sunny from gathak