What does Matthew 15:21 mean?

Jesus had attempted to withdraw from the religious leaders and the crowds before (Matthew 14:34–35). However, too many desperate people wanted His help, willing to travel far and wide and hunt Him down wherever He went. Now Jesus and His disciples make another attempt to withdraw from the people and the Pharisees. He leaves Israel and enters pagan Gentile territory. Specifically, Jesus travels east from Galilee to the district of the Gentile towns of Tyre and Sidon. Jesus was much less likely to be known and pursued outside of Israel.

This is the region to which Jesus had referred when condemning the unwillingness of fellow Israelites to repent (Matthew 11:20–24). In a virtual fulfillment of those words, this thoroughly pagan region will produce a famous example of faith (Matthew 15:22).