U.S. stock index futures were slightly higher Tuesday morning, as traders look ahead to a new earnings season.At around 01:40 a.m. ET, Dow futures rose 55 points, indicating a positive open of more than 57 points. Futures on the S&P and Nasdaq were both marginally higher.Overall, market players are monitoring developments on the trade front. U.S. Treasury Secretary Steven Mnuchin told CNBC that tariffs will go up in December if there is no deal in place with China.”I have every expectation if there’s not a deal those tariffs would go in place, but I expect we’ll have a deal,” Mnuchin said Monday.Furthermore, the U.S. has also decided to stop trade negotiations with Turkey and raised its steel prices to 50%. The decision followed an earlier U.S. announcement to remove all U.S. troops from the northern border of Syria with Turkey.Investors are also looking ahead to a new earnings season. BlackRock, Citigroup, Goldman Sachs, Wells Fargo and J.P. Morgan Chase are set to release their latest performance numbers before the bell. United Airlines and Interactive Brokers will also release earnings after the bell.On the data front, the Empire State manufacturing figures are due to be released at 08:30 a.m. ET.