About 80 percent of Venus' surface is covered in volcanic material. Most of the volcanoes are believed to be inactive, yet there is some evidence to suggest more "recently" activity ("recent" in this context meaning within the last 500 million years).
There are no lava nor caldera (craters created by volcanic collapse), which would seem to suggest the volcanoes have not been active in millennia. However, the surface of Venus has almost no impact craters, which suggests a relatively "new" surface (again, "new" referring to hundreds of millions