The talk with the Russian president is just one of five that Trump has scheduled Saturday. By the end of the day, Trump will have also spoken with leaders from Japan, Germany, France and Australia.
By refusing to respond to the sanctions, Russian President Putin spurned Obama and kept up what has looked like a public bromance with the president-elect, who in turn called him "very smart!"
The nationwide cease-fire is to begin at midnight local time. Russia and Turkey will act as guarantors. The agreement does not include areas under the control of ISIS.
Rex Tillerson, a 64-year-old oil executive, has no government experience. His longtime ties to Russia, including President Vladimir Putin, are already drawing scrutiny from critics.
The Russian leader congratulates Donald Trump and holds out the prospect of cooperation. But with friction on several fronts, it's not clear how they will reduce tensions.