It is more "cycle of karma", with some sects believing you can escape it, and others saying you cannot.
Every action, (or even, decisions toward inaction) has a natural karmic consequence. Karma ALWAYS manifests-- it just might not happen now, or even 10,000 years from now. The consequences of your life choices now might influence your next life, or even your next 100 lives. Typically, actions that cause harm, suffering, or burden to other living creatures produces negative karma, which pushes you "downward" through the realms of existence. The human world is kind of special, because it is neither a celestial heaven, nor a naraka hell. As such, it is a unique place where there is a lot of trans-migration both ways, and where lots of karma of either type can be accumulated.
The more hardcore followers are so devoted to avoiding bad karma (and instead, accruing good karma), that they eat only plants, avoid stepping on insects, etc... / and or-- so devoted to escaping the cycle of rebirth, that they devote themselves entirely to seeking dissolution of the self.
More normal people will avoid meat produced in cruel conditions, or that suffered pain or duress while it was butchered, but are otherwise OK with eating meat-- etc-- as well as being mindful not to be hurtful or callous to the needs of others, even others that cannot be directly seen or interacted with, like hungry ghosts.
I am personally of the opinion that I do not need a karmic reward for doing what is right; If a person is starving from existential hunger, find a way to help them get reliable food. If they are cold, get them warm clothes and a place to stay, etc. Living things have every right to live as any other living thing, and that life should not be expunged for selfish and foolish reasons. etc. I dont need a palace in heaven, or be swayed by seeking a privileged birth in the next incarnation, or any such thing. I get pleasure now, by doing the right thing, and that is sufficient and ample reward.