Can you explain the mechanics of the jink rule in Warhammer 40k and how it impacts gameplay"?

In Warhammer 40k, the jink rule allows a unit to gain a bonus to their saving throws against ranged attacks if they choose to "jink" instead of shooting or running in their turn. This impacts gameplay by giving players a tactical decision to make between offense and defense, as using the jink rule can help protect their units from enemy fire.