Modern Buddhist branches usually include some version of karma, rebirth, realms of existence, enlightenment, monastic authority, sacred texts, and a larger cosmological framework. The details vary widely between Theravada, Mahayana, Vajrayana, Pure Land, Zen, and other schools, but they generally treat Buddhism as a religious-spiritual tradition.
The original Buddhism from long ago lacked the religious elements that evolved since. Today, secular Buddhism is the closest to the original Buddha’s intent.
Secular Buddhism treats Buddhism more as a practical path: mindfulness, compassion, impermanence, non-attachment, suffering, ethical living, and psychological liberation in this life. It is usually skeptical of rebirth, literal karma across lifetimes, heavens, hells, devas, and supernatural claims. The Secular Buddhist Network describes secular Buddhists as skeptical of, or rejecting, supernatural entities or processes such as rebirth; Bhikkhu Bodhi describes the contrast as traditional Buddhism looking mainly to canonical texts, while secular Buddhism looks to modern science and secular values.