South Carolina Sen. Tim Scott is taking steps to run for president, people familiar with his plans said, adding to the stable of Republicans looking to wrest the party mantle from former President Donald Trump. Mr. Scott, the only Black Republican in the Senate, is testing a message with GOP voters in key early states focused on unity and optimism as some Republicans say it is time to move on from the Trump era. Mr. Trump has announced a bid for president in the 2024 election. Jennifer DeCasper, a Scott senior adviser, said he was “excited to share his vision...