Renault is contractually obligated to supply engines to Red Bull and other teams through the 2015 season but has announced that they will not supply engines to Red Bull [or other] teams in the 2016 season. Renault has been in the process of potentially buying the Lotus team, but if that falls through, they could form their own team or depart from Formula One for good.
The 2015 Formula One season continues with the Singapore Grand Prix at Marina Bay at 5 a.m. [PDT] on NBCSN on September 20, 2015.