The Ground Forces of the Russian Federation (Russian: Сухопутные войска Российской Федерации) is the land arm of service of the Russian Armed Forces. The Russian Ground Forces was formed in 1991 after the collapse of the Soviet Union, when the newly formed Russian Federation declared all Red Army units on it's territory as part of the new Ground forces.
In Call of Duty 4: Modern Warfare, the Russian Ground Forces are allies of the USMC and SAS and are part of the Russian Federation Armed Forces, whom remain loyal to the current government of the Russian Federation. This army of Loyalists is led by Sgt. Kamarov. They do not have a multiplayer faction.
The Russian Ground Forces appear in Call of Duty: Modern Warfare (2019), where a part of them make up an opposing faction in the campaign known as Barkov's Forces. They are led by Roman Barkov, a rogue general. Barkov's Forces not only consist of soldiers who pledge their loyalty to Barkov rather than to the Russian Federation, but they also consist of mercenaries and other henchmen who work under Barkov's brutal agenda while they illegally occupy Urzikstan.
At the ending, several Russian soldiers are ambushed and killed by the Al-Qatala, led by their new leader, Khaled Al-Asad, who were seen invading Verdansk. They also appeared as minor friendlies in the final cutscene where Sergeant Kamarov along with John Price, Nikolai and Kate Laswell discuss the intel and begin to talk about forming an alliance to fight back Al-Qatala and liberate Verdansk.
In multiplayer, the Russian Ground Forces appear as the Russian FGF and the Allegiance Mil-Sim.