On Jan. 16, Pokémon Go players will be able to find Machop in abundance with a high chance of it appearing Shiny. It will also learn the dark-type move Payback when evolved during the event period.

Pokémon Gos first Community Day of the new year will feature the fighting-type Pokémon, Machop.
On Jan. 16, 2021, Machop will be spawning in high amounts. At the time of writing this, the Pokémon Go Community Day page has not been updated with a time, but we can assume that the event will take place from 11 a.m. until 5 p.m. in your local time, based on previous Community Days.
Machops evolution line is very useful in both PvP and in raiding, so this is a good chance to add some strong Pokémon to your team. If evolved into a Machamp during the event, it will learn Payback, which isnt a good move for raiding, but is a viable move for PvP.
As usual, the featured Pokémon will spawn with much higher chances to be Shiny during the event period. Stardust obtained from catching Pokémon will also be tripled.
Machop was previously an option on a player vote for a Community Day, which it lost to Rhyhorn. Dratini and Vulpix were also options on the ballot, but the implementation of a Machop Community Day may imply that Dratini and Vulpix may get another shot at the spotlight.
Niantic announced earlier this month that players who purchase a ticket to the upcoming Pokémon Go Tour: Kanto event by Jan. 13 will get free access to special research story lines for January and Februarys Community Days, each of which costs $0.99 separately.