According to your wholesome and unwholesome karma you can be
reborn into any of the following six realms:
3 lower realms: hell, ghost, animal
3 higher realms: human, asura, heaven
Or if you are enlightened and liberated, you attain nirvana and
is free from the cycle of rebirth. Which is our goal. Our goal is
not to be reborn in heaven because life in heaven is still
temporary even though long lived. Eventually one still suffers.
When you are liberated and enlightened (realised your true
nature/the nature of reality), you are freed from all mental
sufferings even as you live. Countless people have attained this
state from the past and even today. Or you can come back into
samsara (the world of suffering, the six realms) as a Bodhisattva
by your own willingness and compassion, take birth, and lead other
beings to enlightenment. A bodhisattva eventually attains full
Buddhahood and leads countless beings to
enlightenment/liberation.
Yes once you attain nirvana the cycle ends....but u need to
attain Nirvana when u r living....