Why doesn't the calendar of Apple's mobile phone have a lunar calendar?

The method of displaying lunar calendar in Apple mobile phone calendar;

1: directly open the settings button on the mobile phone desktop, and drop down to find the "Mail, Address Book, Calendar" button. ?

2. Click to enter the "Mail, Address Book, Calendar" page, drop down to find the relevant options of the calendar, select "Other Calendars" and click to enter the relevant page. ?

3: The current display should be turned off. Select the "Lunar Calendar" option below to close, and the lunar calendar will be displayed.