The international filing date and the priority date are not the same thing.
In the PCT (Patent Cooperation Treaty) system, an international application can be submitted to the PCT receiving office in accordance with PCT regulations within the priority period of 12 months after the domestic application is filed. The earlier domestic filing date is the priority date, and the time when the international application is filed is the international filing date.
For example, I submitted a patent application A in China on January 2, 2010, and then submitted a PCT application B to the State Intellectual Property Office on September 21, 2010, and requested the 2010 Priority of Patent A on January 2, 2019.
In this case, January 2, 2010 is the priority date of application B, and September 21, 2010 is the international filing date.