Hong Kong was leased. Lease expired. Common sense says follow the law.
Caesar used to take entire nations. Then they became Rome. He didn’t lease anything. I miss Caesars.
WIKI
The United Kingdom obtained control over portions of Hong Kong’s territory through three treaties concluded with Qing China after the Opium Wars:
1842 Treaty of Nanking: Hong Kong Island ceded in perpetuity
1860 Convention of Peking: Kowloon Peninsula and Stonecutter’s Island additionally ceded
1898 Convention for the Extension of Hong Kong Territory: the New Territories and outlying islands leased for 99 years until 1997
Despite the finite nature of the New Territories lease, this portion of the colony was developed just as rapidly as, and became highly integrated with, the rest of Hong Kong. As the end of the lease approached, and by the time of serious negotiations over the future status of Hong Kong in the 1980s, it was thought[citation needed] impractical to separate the ceded territories and return only the New Territories to China. In addition, with the scarcity of land and natural resources in Hong Kong Island and Kowloon, large-scale infrastructure investments had been made in the New Territories, with break-evens lying well past 30 June 1997.
https://en.wikipedia.org/wiki/Handover_of_Hong_Kong