There are really only two fundamental aspects or considerations of Buddhism, namely, the conditioned (saṃskṛta) and the unconditioned (asaṃskṛta). We could put it this way, too. There is phenomena like waves of water and the noumenon which is like pure water which is not wave-dependent which is first and prior to its wave phenomena. Samsara, the 12-Nidanas, the three marks of existence, the senses and many more items such as the Five Aggregates (khandhas/skanhdas), fall under the heading of the conditioned. Even practice falls under the heading of the conditioned although it leads to the unconditioned. Nirvana, on the other hand, falls under the heading of the unconditioned. Here we find this distinction fairly obvious (emphasis is mine).
"And the Buddha, the rishi-bull, the guide, taught me of the impermanence of uprising and dukkha; of the unconditioned, of the cessation of dukkha, that are eternal; and of this path, not crooked, straight, auspicious. When I heard (of) the Deathless place, the unconditioned, the Teaching of the Tathagata, the Unrivaled One, I was well and highly restrained in precepts, firm in the Dhamma taught by the Buddha, the most excellent of men. When I know the dustless place, the unconditioned, taught by the Tathagata, the Unrivaled One, I right there reached the calm (supermundane) concentration. That same highest assurance was mine" (Parmatthadīpanī Vimānavatthu-aṭṭakathā).
There is an old saying, all roads lead to Rome. Well, in Buddhism the path leads to the unconditioned, that is nirvana. Nowhere else. The understanding that Buddhism teaches an unconditioned dharma which is the same as the conditioned dharma is, of course, absurd, and makes no sense. It is a product of postmortem Buddhism, in particular Abhidhammas which are sectarian works. This is certainly an attempt to get rid of the problem of ātman/attā which is outside of the purview of the conditioned Five Aggregates by suggesting that this passage pertains to the unconditioned (nirvana) as well as the conditioned, namely, All dhammas are without ātman/attā. But this passage only pertains to the conditioned Five Aggregates according to the Dhammapada-aṭṭakathā, not the ātman which is apart from the conditioned aggregates (later ātman will become Buddha-nature). Nevertheless, this is where some Theravada sects are leading their followers which is a destructive teaching and utterly false. In the Udana-aṭṭakathāwe come across the following:
“that which is the unconditioned element, which has as its own nature that which is the antithesis of all conditioned things, such as earth and so forth, is nibbana [nirvana], for which same reason he (next) says “There, too, monks, I do not speak either of coming” (and so on)" (392).
We see that the unconditioned and the conditioned have distinct and exclusive natures (sabhāvas/svabhāvas). The idea that dharma is a magical overarching term that includes conditioned things and unconditioned nirvana is a fallacy given the polysemic nature of the word "dharma" itself. Nowhere is there such a "dharma" that can include both the conditioned (samsara) and unconditioned (nirvana). Since Dharma can have, basically, four to six meanings context is important to keep in mind. When the Bodhisattva awakened and became Buddha he spoke of the dharma that was unconditioned, namely, nirvana; not conditioned dharmas (sarva dharma). In fact, in the Pali Nikayas there is only one unconditioned dharma (dhamma) this being nirvana (nibbana).
Nirvana, the unconditioned, is not a meditative state like calming, but a state which exists by itself (svabhāva-dharma); which differs from all other things (dharmas) since it is unborn, undying, etc. It is realized by practitioners by various conditioned methods/means, but its own state is by no means dependent on our realization of it. It is somewhat like prospecting for gold. The gold exists whether we find it or not—we don't suddenly make the gold, in other words. We just discover what was always there.