Thursday night's special Mass was held at the Basilica di San Bartolomeo all'Isola Tiberina, or the Church of St. Bartholomew on the Island in Rome.
It's Cupich's titular church, or the church assigned to him as a cardinal.
A titular church symbolizes a cardinal's connection to the pope and the Church of Rome.
It's a tradition that dates back to the early days of the Catholic Church.
St. Bartholomew was founded in the 10th century by the holy Roman emperor.
It's located on the Tiber River.
Thursday's Mass was held for the American Federation of Labor and Congress of Industrial Organizations, a national trade union center that includes the Chicago Federation of Labor.
The group got a special audience with Pope Leo XIV.
"It was amazing, just talking to us about the work we do and reinforcing that everything we do on behalf of workers in our city and state, and that was so uplifting," Don Villar said.
The timing comes as Pope Leo XIV issued a pastoral letter about work and social justice. It was his first pastoral letter.
It's also part of Cupich's celebration of 50 years in the priesthood
In August, the archbishop of Chicago celebrated half a century of Catholic ministry in Chicago at Holy Name Cathedral.
That celebration now continues in Rome, with some familiar hometown faces joining him.
The beloved students from Our Lady of Mount Carmel Academy in Lakeview were altar servers at the Mass.
The Chicago Federation of Labor and the students were just some of the many Chicago groups that were represented at the celebration Mass.
Different Chicago organizations made their way to Rome this week, including Illinois leaders.
The Mass served as a tie to all those groups.
"I think every person from Chicago should feel when they come to Rome, they're coming home. Because not only it's the center of our faith, but because the Holy Father is here as one of us," Cupich said.
The cardinal's message was to find the good with a sense of patience.
"I think that we need to look for ways in which we once again believe that in each human being there is goodness, and we just have to be patient to let it come out," Cupich said.
It's a message he hopes is carried on through the young faces in the crowd.
"It really connects my faith, and this whole journey connects to my faith in God and Jesus and blessing that we are able to be here today," Our Lady of Mount Carmel seventh-grader Patrick Passamani said.