In a Reddit AMA, 4A Games revealed that it may implement the latest and improved version of DLSS in Metro Exodus in the future. However, and before you start celebrating, there aren’t currently any plans for such a thing.
As a 4A Games developer said when asked about it:
“We may implement it in the future, but for now, no. There are some systems that we would have to rework in order to support the new priorities of the updated DLSS.”