Stock futures were flat after all three major U.S. indexes finished higher, with investors focused on Nvidia's earnings report due after the bell and whether the chipmaker is becoming more or less dependent on hyperscalers such as Amazon, Google and Microsoft. Canada announced retaliatory tariffs on more than 700 U.S. goods, totaling around $20 billion and matching the Trump administration's 50% duties dollar for dollar. The measures, effective Sept. 8, include a 50% tariff on American steel and aluminum, double the current rate. Iran and Oman discussed a temporary joint shipping route through the Strait of Hormuz and a possible mine-clearing mission as tanker traffic remains sharply below prewar levels, while crude prices fell after dropping more than 3% the previous session. The Department of Health and Human Services plans two new deputy commissioner roles at the Food and Drug Administration (U.S. drug regulator), including one focused on technology and health AI. Waymo plans to launch driverless rides in Germany by the end of 2027 after phased testing begins in Munich, its first European Union market. Bitcoin rose above $81,000 on Tuesday.