What does Matthew 16:1 mean?

Jesus and His disciples have returned to the west side of the Sea of Galilee after spending some time in the region of the Gentiles (Matthew 15:21). Matthew next records that Jesus is approached by a group of Jewish religious leaders that includes both Pharisees and Sadducees. This is noteworthy since these two sects did not get along easily. They often openly opposed each other. The Pharisees were Israel's teachers, with the closest connection to the people. The Sadducees held political power and were found mostly in and around Jerusalem. The fact that they approach Jesus together may show that they had unified to oppose this threat to their power and the status quo in Israel.

Based on other incidents, it's clear these men did not come to sincerely ask for evidence that Jesus was the Messiah (Matthew 12:1–2; 9–10, 24). Rather, they came hoping to catch Him doing something for which they could discredit Him or end His public ministry. These men are already aware of many miraculous acts done by Jesus (Matthew 12:13–14, 22), including healing diseases and afflictions, and casting out demons. Ignoring all evidence, while asking for more, is a sign of dishonesty.

Performing at the beck and call of hardened skeptics is not part of Jesus' mission; He will not satisfy their request.