According to Einstein's theory of relativity, Newton's laws of motion hold true in what is called the "Newtonian limit," which is when speeds are much smaller than the speed of light and gravitational fields are weak. In this limit, Newton's laws provide an accurate description of the motion of objects.
However, in the general theory of relativity, Einstein's theory of gravity, the concept of inertial frames of reference is expanded. Inertial frames are frames of reference in which Newton's laws of motion hold true without the presence of any external forces. In the general theory of relativity, the equivalence principle states that the effects of gravity are indistinguishable from the effects of acceleration. This means that in a freely falling frame of reference, which is considered an inertial frame in general relativity, objects will follow Newton's laws of motion as if there were no gravitational forces acting on them.
In situations involving strong gravitational fields, high speeds approaching the speed of light, or when considering the behavior of light itself, the effects of general relativity become significant, and Newton's laws no longer provide an accurate description. In these cases, the theory of relativity must be employed.
So, while Newton's laws of motion are a valid approximation in the Newtonian limit, the more comprehensive theory of general relativity is necessary for a complete description of the motion of objects in all frames of reference, particularly in situations involving strong gravity or high speeds.