According to Republic Act No. 10966, December 8, 2021, is a HOLIDAY. This is also included in the President Proclamation for the Declaration of Regular Holidays and Special (Non-Working) Days for 2021.
The Republic Act. No. 10966 also known as An Act Declaring December 8 of Every Year a Special Non-Working Holiday in the Entire Country to Commemorate the Feast of the Immaculate Conception of Mary, the Principal Patroness of the Philippines.”