Honor & Fame in Red Dead Redemption 2 (RDR2) is a mechanic that rewards/punishes players based on their in-game behavior. Since the first section covers Honor, you may skip down to learn more about Fame, by scrolling down.
Honor in RDR2
Honor in Red Dead Redemption 2 is a system which keeps track of Arthur Morgan's behavior throughout the whole game. Players' actions can add positive/negative points to their Honor based off of their actions in open play. The severity of one's actions can determine how much their honor shifts per action. For example: if a player shoots a civilian for no reason, their honor falls a lot less than if they were too shoot and kill a Lawman; however if the player helps a stranger in an encounter or catch a bounty, their honor level increases.
Accumulating a specific amount of honor (or dishonor) will result in reaching a milestone, which the player will be notified of. Whether positive or negative, each milestone will grant Arthur will special treatment from certain NPC groups, as well as monetary bonuses. However this isn't a case of unlocking it and keeping it permanently; players must maintain or improve their (dis)honor level to continue to receive the same perks. ALTERNATIVELY, players may equip a bandana to hide their faces, preventing their Honor from shifting eitherway.
In the first Red Dead Redemption, there were a total of 7 levels on the Honor spectrum which granted players special perks:
Honor Ranks (Not Official)
Honor Point Distribution
Performing different actions have different set honor values that are rewarded to the player. These are yet to be confirmed in RDR2.
Fame in RDR2
While the Honor mechanic judges and rewards/sanctions player's based on the morality of their actions, the Fame mechanic rewards players for their participation and performance. This means the player can raise Arthur's Fame by participating in any activity, regardless whether it is regarded as honorable or dishonorable. For example: killing anyone, even innocents, will raise the player's fame and will shift according to the ethics of the action.
Arthur's claim to fame can come in a variety of ways and not solely through homicide, although that is the fastest approach. Winning games, volunteering, helping people, and bounty hunting, are just to name a few methods. Just like Honor, there are different levels to Arthur's fame that each come with their own perks, though not specified for RDR2 either.
Fame Ranks (Not Official)
Fame Point Distribution