The two presidents are scheduled to hold a telephone conversation at 12:30 p.m. (16:30 GMT).
Where did you get that information? If the two president will have a talk they will not broadcast it to avoid people spying on their conversation. But if the schedule of the call was broadcasted then they will not discuss confidential and official matters. Probably they will discuss some plans and programs for the development of both countries.
Do the press services of both presidents announced the intention to hold a phone conversation between Trump and Putin. I'm pretty sure that none of which they do not agree. Very different interests of America and Russia.