why do the cubs have 21 on their jerseys

The Chicago Cubs have the number 21 on their jerseys as part of an MLB-wide tribute to honor Roberto Clemente. Clemente, a legendary Puerto Rican Hall of Famer who wore the number 21 throughout his career, is celebrated every year on September 15, known as Roberto Clemente Day. On this day, all MLB players, managers, and coaches wear a No. 21 patch to commemorate his legacy, and Puerto Rican players, award nominees, and some others may wear the number 21 on their jerseys in his honor. The Cubs, like other teams, participate in this tribute by wearing the 21 patch and sometimes players wear number 21 to reflect their respect for Clemente’s humanitarian work and baseball achievements.