While no person can predict the future, if the past is any indication, there will be military conflict between groups of people as long as human beings exist. The military has always, however, been on the cutting edge of technology, and future warfare, while speculated on in video games, can certainly be understood as a concept.
One of the tasks of the military is planning for the next war, rather than refighting the last one. The nature of warfare is constantly changing. At the beginning of World War II, for example, naval strategists still largely expected battleships to play a major role, when in fact aircraft carriers became the dominant sea force.
Stealth technology has the potential to change future warfare. Scientists have been working on various materials that reduce both the thermal and visual signature of aircraft, making them all but invisible to the enemy. Outer space may prove to be a new frontier in future warfare, not necessarily in terms of fighting soldiers, but in the deployment of weaponry which can be used to attack targets on Earth.
However, the most potentially frightening aspect of future warfare could be the use of robots as soldiers. Lethal autonomous robots are not just the stuff of the Terminator films, but a technology that could emerge on future battlefields. Robots, like drones, could be used remotely, saving the lives of soldiers but potentially making warfare more lethal in the war zone.