The Tetrarch of Galilee and Perea ruled the rump of his family's kingdom. All left under his direct control was Galilee to the north and Pera (modern-day western Jordan). His family of Jewish gentiles were a vague shadow of the great kings like David and Solomon. He was in Jerusalem to celebrate Passover. Ultimately, he would represent how some people completely waste away God's gifts.
The Roman governor of Judea represented the Emperor Augustus by ruling the Holy Land directly for Rome. Jerusalem was his capital and the influx of Jews from across the Empire, Arabia, and Persia for the Passover celebration required his direct oversight. Pilate represented the might of worldly powers but his violence and ultimately cowardliness represented the limits of worldly gains.
The high priest of the Temple lived, worked, and prayed in Jerusalem. He would need to oversee the Passover. During his time on Passover/Good Friday, Caiaphas shows the tragedy of making religion an ideology and political calculations while ignoring the divine.
The Christ entered Jerusalem knowing what was going to happen. While some like Caiaphas feared Jesus would use Passover to start a revolution, but instead He came to complete the feast. He would also turn the focus of the faith from the city of Jerusalem to the universal Jerusalem.