At this year's International Astronautical Congress, NASA and Russia's space agency Roscosmos signed a joint statement expressing their intent to work collaboratively towards the development of a space station further out from Earth, orbiting the Moon, as a staging point for both lunar surface exploration and deeper space science.
This is part of NASA's expressed desire to explore and develop its so-called "deep space gateway" concept, which it intends to be a strategic base from which to expand the range and capabilities of human space exploration. NASA wants to get humans out into space beyond the Moon, in other words, and the gateway concept would establish an orbital space station in the vicinity of the Moon to help make this a more practical possibility.
"While the deep space gateway is still in concept formulation, NASA is pleased to see growing international interest in moving into cislunar space as the next step for advancing human space exploration," said Robert Lightfoot, NASA's acting administrator at NASA Headquarters in Washington said in a NASA press release announcing the news. "Statements such as this one signed with Roscosmos show the gateway concept as an enabler to the kind of exploration architecture that is affordable and sustainable."
This is still very early stages in terms of potential collaboration between Roscosmos and NASA – you might say it's an agreement to possibly agree to work together in the future. But it's a good sign for open dialogue about the plan to put a science and exploration facility in orbit around the moon in future.