The US and western countries have given hundreds of millions of dollars during the past seventeen years to Afghanistan to reconstruct and build its security infrastructures. However, low troop morale, widespread corruption among commanders and officials, and nefarious intervention by multiple external countries has kept large parts of Afghanistan unstable. The stalemate of war has frustrated both sides because no winning horizon is foreseeable
for the warring parties. This situation made the US President Donald Trump’s administration sent veteran Afghan-born diplomat Zalmay Khalilzad to Afghanistan with a clear mission: Finding an end to America’s 17-year-long war with the Taliban.
Thus, there are several key factors making some form of ceasefire and/or peace possible, if not necessarily fully probable in the war torn Afghanistan. First, according to the military experts, the Afghan Special Forces are actually fairly effective. Though they do not constitute a large percentage of Afghan forces, they are well trained and well commanded and they have played a key role in preventing Taliban to hold large towns or cities for long. Second, most of the country’s thirty-five million people are not just tired of war, but they are expressing their discontent in novel ways. For example, the breakthrough ceasefire in June also coincided with a young-person-led “Peace Caravan” that traveled from Helmand province on foot to Kabul to demand a cessation to the conflict. Third, there is fresh evidence that many Taliban commanders and fighters have also grown weary of the carnage and they are not fully committed to the group as the past. 
Fourth, the United States and its allies have not only increased their attacks on the Taliban as of late, but it has for the first time in the conflict engaged the Taliban directly at the negotiating table—with Washington also naming a  special envoy for the conflict in the seasoned diplomat Zalmay Khalilzad. And he started direct negotiations with Taliban although the US had long maintained that it was proper for the Taliban to deal diplomatically only with the Afghan government.
Finally, what may prove most decisive of these factors, the notorious Great Game—in which outside powers have intervened in and jousted over Afghanistan for a century and a half—is proving surprisingly propitious in terms of a rare coinciding of the interests of these countries? Specifically, it appears that the stability of Afghanistan is now squarely in the interests of all of parties, including the US, Europe, Turkey, China, India, Russia, Iran, Pakistan and the Gulf countries.
For Americans and Europeans Afghan stability is obviously a stated goal and consistent pursuit, as well as the Turks and the Indians—and for the most part Saudi Arabia and its fellow Gulf countries, who have a shared interest in keeping insurgents at bay. Stability of Afghanistan is in the interest of Iran because her interests lie in trading as much as possible with all of its neighbors, coming out of sanctions and more recently being subject to them again. For example, Iran is working with both India and Afghanistan to build up its Chabahar Port, which is to connect to the latter by rail. In addition, eastern Iran is particularly prone to drought, and the rivers it shares with Afghanistan flow downhill from the Afghan side of the border.
Russia also gains no benefits from insurgencies and it is wary that, and feeding the insurgency in Afghanistan has led to part of it to spread to within what it defines as its sphere of influence in Central Asia. In fact, Russia, Iran, China and Pakistan all have encouraged the Taliban to join to the peace talks.
China is rapidly building its Belt and Road Initiative, as a strategic project, across the region, thought it did make a highly impactful decision to cut Afghanistan out of its immediate plans by choosing Pakistan to be the recipient of a massive road/rail/port network that has come to be called the Chinese Pakistan Economic Corridor. Yet the Chinese have recently come to realize that it is in their interest to build spurs off of CPEC into Afghanistan, so as to connect with the Central Asian states. Further, China may slowly be coming to realize that it is capable of accomplishing something than even the United States cannot, viz. pressuring Pakistan to end its support of the Haqqani network, one of the most fearsome elements of the Taliban network (due to CPEC it has enormous leverage over the Pakistanis).
Finally, Pakistan has long kept what it calls “a buffer zone” in place in Afghanistan by hosting and funding the Haqqanis and other Taliban leaders/forces. It has done this partially to achieve “strategic heft” against India, but primarily because it has not wanted Afghanistan to become stable and develop ahead of it. In light of Afghanistan’s sizable deposits of oil and gas and rare earth minerals, Pakistani leaders primarily in its security forces have aimed to keep Afghanistan unstable. But now that Pakistan will almost certainly develop sooner than its northern neighbor due precisely to CPEC, it stands to benefit from a stable Afghanistan—not only from the diplomatic kudos it will receive for ending its Taliban support, but being energy-poor it needs oil and electricity from energy-rich Central Asia to transit in grid and pipeline networks across Afghanistan. The Afghans are particularly savvy at promoting energy and transport infrastructure projects with the Central Asians, which bodes well for Pakistan.
In a nutshell, the world powers and Afghan neighbors have always been interested to have a foothold in Afghanistan. As such they had their own national-security interests at stake in Afghanistan, and intervened there regularly whether invited or uninvited. But each of them now share, for the first time in history, joint interests in a stable Afghanistan.