I don't use the term #leftunity because there's a lot of discourse around it, but I do believe that on the ground, in the streets, and on many particular issues, #communist and #anarchist people can work together (and must). I think that better terms might be #unitedfront or #leftalliance, as unity as a term papers over meaningful differences in the two political ideologies.
I think that #anarchists as a whole, could stand to be more critically supportive of past and current socialist experiments around the world, while #communists (#marxistleninists and #maoists) should accept that there is sound anarchist theory that might not be reflected in many self-identified anarchists. After all, how many Leninists can honestly claim to have done their own reading?