President Trump officially on trial as impeachment proceedings kick off, Hillary Clinton unleashes on one-time rival Bernie Sanders, and first U.S. case of deadly mystery virus confirmed. Watch “NBC Nightly News With Lester Holt” at 6:30 p.m. ET / 5:30 p.m. CT (or check your local listings). 1:09 Trump's Impeachment Trial Begins With Fierce Senate Battle 5:11 McConnell Unveils Last-Minute Surprise In Rules Debate 6:09 Trump Calls Impeachment Trial A 'Hoax' At Davos Conference 6:52 Trump Clashes With Climate Activist Greta Thunberg At Davos 7:43 Ukraine's President Expected At Davos Summit Tomorrow 7:57 Opening Arguments Expected In Trump's Trial Tomorrow 8:50 Hillary Clinton Slams Bernie Sanders: 'Nobody Likes Him' 10:11 First U.S. Case Of Deadly Mystery Virus Confirmed 12:21 Oprah Winfrey Breaks Silence On Controversial Documentary 14:10 Dangerous Deep Freeze & New Storm Threat On The Move » Subscribe to NBC News: nbcnews.to/SubscribeToNBC » Watch more NBC video: bit.ly/MoreNBCNews Connect with NBC Nightly News online! NBC News App: smart.link/5d0cd9df61b80 Breaking News Alerts: link.nbcnews.com/join/5cj/breaking-news-signup?cid=sm_npd_nn_yt_bn-clip_190621 Visit NBCNightlyNews.com: nbcnews.to/2wFotQ8 Find Nightly News on Facebook: bit.ly/2TZ1PhF Follow Nightly News on Twitter: bit.ly/1yFY2s4 Follow Nightly News on Instagram: bit.ly/2tEncJD NBC News Digital is a collection of innovative and powerful news brands that deliver compelling, diverse and engaging news stories. NBC News Digital features NBCNews.com, MSNBC.com, TODAY.com, Nightly News, Meet the Press, Dateline, and the existing apps and digital extensions of these respective properties. We deliver the best in breaking news, live video coverage, original journalism and segments from your favorite NBC News Shows. NBC Nightly News Broadcast (Full) - January 21st, 2020 | NBC Nightly News