Modern day Palestinian Arabs have as their ancestors Arabs, Egyptians, Judeans, Samaritans, Arameans, Moabites, Edomites, and yes Philistines.
Modern day Jews have among their ancestors Judeans, Edomites and yes, Philistines.
The Philistines as a nation were absorbed by their neighbours well before the Assyrian conquess of the 8th century BC
The Jews (Hebrews) originated from Abraham, Isaac, and Jacob.
Some of the Philistines may have been assimilated into the Jewish population - but not the other way around - as other groups over time have also mixed in with part of the Jewish population.