Not unlikely Christianity was influenced by Buddhism, https://en.wikipedia.org/wiki/Buddhism_and_Christianity.
And certain groups, especially a Gnostic creed Catharism, has a lot of similarities.
The most we have are faint gestures at how some Buddhists could indeed have been alive in the same place, at the same time, as early Christians. But Christ himself, as far as we know, never referenced Buddha or any Buddhist works, never interacted with a practitioner of the faith (or even referred to one), and all the same applies to the Apostles.
E.g. nobody would suggest that Buddhism was particularly influenced by Greek religious thinking, but we know with certainty that Greeks were present in the region due to their service in the Persian empire of the time.
I recommend the book "Sacred Knowledge" by Willian Richards and the concept of cosmic unity (as the first "birth matrix") from "Realms of the Human Unconscious: Observations from LSD" by Stanislav Groff.
There ideas are in every culture and religion.