Mary Bruce has details on the release of American citizens Evan Gershkovich, Paul Whelan, and Alsu Kurmesheva from Russia in a 24-prisoner exchange after painstaking negotiations, and Whit Johnson speaks with Whelan's twin brother, David, about how the swap unfolded and what happens next; Maggie Rulli reports on Team USA's day at the Paris Olympics, where gymnast Simone Biles and swimmer Katie Ledecky made history; Matt Rivers has new details on the assassination of Hamas leader Ismail Haniyeh in Tehran, with sources confirming he was killed by an explosive smuggled to his room months ago as part of an Israeli plot; and more on tonight's broadcast of World News Tonight with David Muir.