U.S. stock index futures were slightly lower Thursday morning.At around 01:50 a.m. ET, Dow futures fell 35 points, indicating a negative open of more than 26 points. Futures on the S&P and Nasdaq were both marginally lower.Wall Street ended Wednesday on a higher note after President Trump said that a U.S.-China trade deal could arrive sooner-than-expected. Both countries have engaged on a tit-for-tat tariff war since 2018.Meanwhile, investors are also monitoring an impeachment inquiry started at the House of Representatives on Tuesday, in relation to a call between the President and his Ukrainian counterpart, Volodymyr Zelensky. A transcript from the call, released Wednesday, did not appear to show and explicit quid pro quo by Donald Trump. However, more details of their phone conversation are yet to be released.On the data front, there will be jobless claims figures out at 08:30 a.m. ET. At the same time, it will also be released the third reading of real GDP (growth domestic product) data from the second quarter of this year.In corporate news, Carnival and Vail Resorts will be reporting.Several Fed members will also be making speeches throughout the day, including St Louis Fed President James Bullard at 10:00 a.m. ET.