It is impossible to predict which countries will be involved in World War III. While some sources suggest that the United States, Russia, and China are likely to be involved, others claim that the major player at the start of the worldwide conflict would actually be China. However, it is important to note that these are just predictions and not based on any concrete evidence. It is also worth noting that the possibility of a third world war has been anticipated and planned for by military and civil authorities in many countries during the Cold War years. Ultimately, it is impossible to predict which countries will be involved in World War III, and it is important to work towards peace and diplomacy to prevent such a catastrophic event from occurring.