Methods of developing genetically engineered immune cells for immunotherapy, which can be endowed with Chimeric Antigen Receptors targeting an antigen marker that is common to both the pathological cells and said immune cells (ex: CD38, CS1 or CD70) by the fact that the genes encoding said markers are inactivated in said immune cells by a rare cutting endonuclease such as TALEN, Cas9 or argonaute.