North Korea and China have recently negotiated a new agreement in the hopes of easing recent border tension. The tension and agreement follow several shooting incidents in which North Korean Border Patrol fired at Chinese citizens who crossed the border.
One source (unnamed for security reasons) explained to Daily NK, a news source devoted to providing news on North Korea, that "From this past Spring until last month, North Korean soldiers shot and killed several Chinese near the border but North Korea failed to apologize properly, so the Chinese government proposed [the agreement] as a way to protect their citizens."
The agreement signed would allow for the following: "China will raise customs duties three-fold on goods entering the country (from North Korea) if North Korean border guards 'indiscriminately' and 'recklessly' shoot and kill a Chinese national. The agreement also requires North Korea to compensate a shooting victim with RMB 1,200,000 (around USD 175,922)"
The details of the agreement are able to hold more sway than normal over North Korea as the COVID-19 border closure would mean North Korea would be unable to import many necessities from China. Additionally, as of September 11th, the Ministry of State Security and General Staff Department mandated that North Korean border patrol adhere to the agreement.
However, Daily NK had also reported earlier in September that North Korea had established "buffer zones" in which border patrol officers are ordered to shoot any who enter. Although the agreement between North Korea and China was meant to relieve tension, it seems as though it will still be quite some time before North Korea opens borders to China.