Q&A: How does Existentialism and Marxism coexist with each other?

The two philosophies of Existentialism and Marxism seem to contradict with each other.  One places an importance on the individual and his/her freedom and the other stresses the importance of the group and their place in history.  While it appears that that two cannot coexist, there is actually a overlap of the two philosophies.  Existentialism wants the most freedom for the individual, and Marxism wants the most freedom for the masses.  In a Marxist society, both goals could be met.  A person's private freedom does not have to infringe upon the private freedoms of others.
Of course, young Sartre's radical freedom is at odds with Marxism, as is other existentialist philosophers. Some of the ideas behind existentialism like the idea that life has no meaning can push people to focus on this life and its ills and not to reach for an afterlife that has no empirical evidence for.  Authenticity is a common theme in both philosophies; Marxism wants people to work as how they want to and existentialists want people to be true to themselves.  Both ideologies have some common ground and both could easily mix if they were willing to flex a bit for the other.