The Cherokee were forced to move in spite of the Supreme Court's ruling in Worcester v. Georgia because President Jackson wanted to move them regardless and he did not care about what the Court had decided.
In Worcester v. Georgia, the Court had decided that the United States did not have the power to force laws and decisions on land that belonged to the Native Americans. President Jackson did not care, he still wanted to move the Native Americans and expand America westward. The United States had acquired new land to the west, meaning there was new land to be discovered and used. The Native Americans were there though, so President Jackson was set on moving them to where present-day Oklahoma is located.
When the Native Americans did not move, this caused President Jackson to send troops and remove them by force. They were then forced to walk to where present-day Oklahoma is, on a treacherous journey. This walk is coined as the Trail of Tears and is known for being a very terrible part of American history. Many Native Americans ended up dying on this walk, as weather conditions were terrible, mountains were in their way, they had little food, and often caught diseases.