This class combination has some measure of direct synergy with both classes favoring dexterity, but the direct interlock stops there; the bard is a spellcaster and the ranger (usually) is not. However, where this combination truly comes into its own is outside of combat. Rangers are the masters of the exploration pillar and bards are the masters of the social pillar. The sheer versatility and number of things to do creates a dynamic where these characters are virtually never going to be the best in any given situation, but there will also almost never be a set of circumstances where there isn’t something meaningful that they can do.
A stronger focus on bard levels means more magic and trickery and probably more of a support role in combat, using battle hymns and ranged weapons from the back. A higher focus on ranger probably indicates a wandering wilderness expert that can show surprising amounts of charm in settled areas. An even mix of the two is a character of supreme versatility that can change their tactics on the fly and probably does something different in every situation, adapting in real time to the circumstances.
[[Synergy Feats for Multiclassers#Bard w/ Ranger|Bard - Ranger chains and ideas]]