How did the two pieces of jade from the ancient city tomb come out? What happened to those two pieces of jade?

There is no clear explanation in the online drama. The netizen suggested that the two children put it in Hu Bayi's pocket.

In fact, there is no positive explanation about these two jade TV dramas, saying how these two jade pieces got into their pockets. Only after Wang Pangzi, Hu Bayi and Eiko came up again, did they speculate that it was because they had brought these two little ancestors, and also because these two little ancestors thanked them for putting them in the grave, so they put the two jade pieces they had taken a fancy to from the beginning in their pockets.

The story introduction of the ancient city;

Hu Bayi (Jin Dong) went to the countryside and came to Ganggangyingzi on the border between China and Mongolia. He took the only book left at home, The Secret of Sixteen Characters of Yin and Yang Feng Shui, and recited the words in the book at leisure. Later he joined the army and went to Tibet. When he met an avalanche and fell into a huge trench, Hu Bayi escaped secretly with his own grave.

After demobilization, Hu Bayi and his good friend Wang Pangzi (Zhao Da) joined an archaeological team and went to Xinjiang for archaeology. A group of people went through hardships and dangers to the ruins of the ancient city in the Taklimakan desert and entered the underground "ghost hole". There are many organs and traps in the cave. This mysterious ghost cave seems to be controlled by a prophet.