One of the two trekkers, who were lost in the wilderness of Nepal for 49 days, was recently rescued. Unfortunately, the other trekker died just 3 days before the rescue was made. There has been few cases of trekkers missing in the Langtang region before.
Backstory

Liang Shang Yuen and girlfriend Liu Chen Chun, aged 21 and 19 respectively, were heading towards Langtang through Dhading’s Tipling and Pangsang Pass on February without a guide.
On March 11, they tried to descend in the hopes of finding a settlement near the river down valley. While descending, they slipped down on the snow and were trapped. Being unable to climb out of the place, they took shelter under a waterfall.
They survived 4-5 days on the food they had been carrying. After their supply ended, they managed to survive only on water and salt until they were discovered by the search team. Unfortunately, Liu Chen died just 3 days before the rescue team found them.
Rescue
A rescue was made with the joint effort of Taiwanese Embassy, Asian Trekking and Simrik Airlines.
21-year-old Liang Sheng Yueh was found Wednesday on a ledge under a waterfall and was flown by helicopter to a hospital in the capital, Kathmandu. He said the body of his girlfriend, 19-year-old Liu Chen Chun, was also taken to the capital.
The parents of the couple arrived in Kathmandu on March to find the whereabouts of their children. The rescue was assembled to locate the couple. Rescuers first scoured the area for two weeks before suspending their search, but resumed the search on April 20.
The team spotted the red tent almost after a month of search. Liang was found living inside the tent. The helicopter was immediately beckoned to evacuate the distressed trekker. Liang was transported to the hospital in Kathmandu. Another helicopter transported the body of Liu to Kathmandu.
He appears exhausted and lost some 30 kilograms of body weight. He was suffering from severe malnutrition. His foot was covered with maggots and hair full of lice. Despite having to live like that for 47 days, he appears to be mostly normal. ~Dr. Ajay Singh Thapa
Lantang Region
Langtang is a popular trekking region in Nepal. Due to its discreet nature, most of the region remains unexplored or offbeat for trekking. There has been few cases where the trekkers went missing while trekking in Langtang.
It was notified by the Government that a trekker must be accompanied by a certified guide while entering the region, back in 2012. The notice came after the severed body of a teenager Debbie Maveau was found who went missing in Langtang.
Most of the trek regions in Nepal are located in the remote areas, hence, taking a guide along becomes necessary. Anytime between March-May and September-November is considered best for the trekking.