Some comments about Newtonian mechanics and special relativity.
Newtonian mechanics features relativity of motion; if you are in a car on a freeway and you are passing a truck, the truck is moving backwards relative to you, and forwards relative to the road. We normally omit what we consider mentioning what something's motion is relative to, because it is usually its environment. But when it is not clear from such a context, we often get more specific, like distinguishing between an airplane's airspeed and groundspeed.
Galileo had done a thought experiment about relativity of motion. Imagine that you are below decks in a ship; how could you tell that you were moving? He proposed that there was no fundamental physical difference between these states, and that insight became part of Newtonian mechanics.
But every object nevertheless "sees" the same time between space-time points. Or does it? A first hint of trouble was with Maxwell's equations of the electric and magnetic fields; they have wave solutions with the waves traveling at a constant speed in a vacuum: c. However, that is contrary to Newtonian mechanics, and that gave physicists a LOT of headaches in the late 19th century. Albert Einstein got the correct solution: special relativity, which modifies Newtonian mechanics to be consistent with Maxwellian electrodynamics. But a side effect is that objects don't all "see" the same time separation between space-time points, any more than they "see" the same space separation between them. It is a VERY tiny difference in familiar circumstances, but at speeds approaching c it can become VERY large.
Back to quantum mechanics. In general, it is non-relativistic; it depends on having some well-defined time coordinate. However, it does not exclude special relativity; including it puts in some rather strong constraints, because time gets mixed up with space.
The result is relativistic quantum field theory; a paradigm that includes quantum electrodynamics and related theories. And QED itself is now recognized to be a subset of a bigger theory, the electroweak theory. Yes, electromagnetic and weak interactions forming parts of a single interaction.