Is a word Filipinos common noun?

No, the plural noun 'Filipinos' is a proper noun, the name of the people of or from the Philippines.

A common noun is a general Word for a person, a place, or a thing.

A common noun for the proper noun 'Filipinos' is peopleor citizens.

A common noun for the proper noun 'Philippines' is country or nation.

Note: You have correctly capitalized the noun 'Filipinos'. A proper noun is always capitalized.