Weapons in which the energy is provided by nuclear fission or fusion have only twice in history been detonated outside of a controlled test environment, in the Hiroshima and Nagasaki events in World War II.
Since then, the world has nearly gone to nuclear war as a result of international conflict (during the Cuban Missile Crisis) and by accident. (Indeed, there have been a number of narrowly-averted accidental nuclear detonations. See this timeline for a sobering look at how close we have come.)
This question (which any sane person will hope resolves negatively) regards the probability that a nuclear war will occur by Jan 1, 2070. (Different questions address this separately, but none directly.) There is a great paucity of public and useful estimates of this probability. See for example this paper for an outline of considerations (but no bottom-line numbers.)