The point at which the heat flow will stop is when two objects reach thermal equilibrium.
When the two objects reach thermal equilibrium it means they have the same temperature and there is no longer a difference in temperature between them.
Essentially when the heat transfer from the object that is warmer to the object that is cooler ceases due to the equalized temperatures.
Heat always flows from a hotter object to a cooler object so the temperature difference drives the heat transfer.
And once the temperatures are the same, there is then no heat flow and the system is said to be in thermal equilibrium.
Objects that are at thermal equilibrium with each other are at the same temperature and can exchange energy between them.
Objects that are in contact have a tendency to move toward thermal equilibrium.
Two physical systems are in thermal equilibrium if there is no net flow of any thermal energy between them when they are connected by a path permeable to heat.
Thermal equilibrium also obeys the zeroth law of thermodynamics.