What does Santa have to do with Jesus

There is no direct relationship between Santa Claus and Jesus Christ.

However, Christmas is celebrated every year on 25th December to celebrate the birth anniversary of Jesus.

Santa Claus is a figure based on the life of St. Nicholas, one of the apostles of Jesus who gave generously to those in need during his life.

Since St. Nicholas followed Jesus's instruction to be charitable, Christmas
is celebrated keeping this virtue in mind.