The left/marxist left is in trouble on the issue of religion since its legacy has become one more of the social conditioning instruments (dysfunctional currently as a lesser cult) that promote an ideology.
The public needs something better than historical materialism to replace the Axial Age religions. Even if a neo-communist movement focused on atheism it would still be a long way off from anything a new generation would find amenable.
A whole new communist (ditto socialist, general leftist) perspective is needed, and it cant be a canned belief system.
In fact the system is drifting into a post-religious secular junk thought complex based on consumer idiocy, the control factor of machiavellian politicians, academic social conditioning instruments, secular humanist/new age cultic garbage, and the general tenor of scientism, now with a set of self-help reductions of buddhism/yoga to mindfulness fads, etc…
In a word, a large zero. But changing that would not be easy, and the left is about a century behind.