Almost all the immortals in China are 100% Taoists.
Taoism, as well as medicine, originated from the technique of Huang Lao. Taoist medical terms are authentic Huang Lao medicine (focusing on longevity and long-term vision), while the traditional Chinese medicine is a secular version of Huang Lao medicine (focusing on saving blind sheep from death and making up for hindsight).
In fact, the true Tao is really either to worship God or to live in seclusion in the mountains.