In 2018 and beyond will futures contracts retain the favorable 60/40 tax treatment? Or has that been modified/repealed
The 60/40 tax treatment for futures is laid out in 26 U.S.C. 1256. That section defines that 60/40 tax treatment (1256(a)), and also defines what futures are eligible for that tax treatment (1256(b)). Thus, searching the enacted version of H.R. 1, the Tax Cut and Jobs Act, for "1256" should produce all changes to the favorable 60/40 tax treatment.
H.R. 1 mentions section 1256 only once, in Section 13306(a), which changes the ability to deduct as a business expense fines or penalties--i.e. that section does not change the tax treatment of 1256 securities.