In Hinduism, Chiranjeevi is the term used to refer to those people who live forever. There are several well known Chiranjeevis in Hindu Scriptures. They are Sage Markandeya, Mahabali, Parashurama, Vibhishana, Hanuman, Jambavan, Sage Vyasa, Kripacharya, and Ashwathama.
Please note that as per some texts there are only seven Chiranjeevis. Then Sage Markandeya and Jambavan are not counted.
It must be noted the Chiranjeevi (s) mentioned in Hindu religion were born as mortals and later on became Chiranjeevi (s) due to boon, blessing or curse.
अश्वत्थामा बलिर्व्यासो, हनुमानश्च बिभीषण|
कृप: परशुराम सप्तैते चिरंजीविन:|
Some scholars are of the view that the concept of Chiranjeevi does not mean immortality but that they live much longer than humans. For this they point out demigods (devas) who became immortals by drinking the Amrit or elixir of life during the Samudra Manthan.