There's quite a bit of controversy around the topic of past lives. Many religions hold strict beliefs that we only have one life on this earth. But other religions speak of many incarnations and not even just as humans!
I have many friends who strongly believe they have had previous lives here. I, myself, have had very vivid dreams about living someone else's life during WWII. Dr. Ian Stevens of the University of Virginia studied cases of reincarnation in India and wrote several case studies about current life birthmarks corresponding with death wounds in a previous life.
I have been watching a TV show on Amazon Prime called the Ghost in my Child (A&E). It is a 2 season show with multiple episodes covering interviews and recounts of what parents believe to be their children remembering past lives. Interesting and worth a view if this is an area of interest for you;)