Belmonte Beitia, Juan. Pérez García, Victor M.. Martínez Rubio, Álvaro. 

Chimeric Antigen Receptor T (CAR-T) cell therapy has been proven to be successful against different leukaemias and lymphomas. This paper makes an analytical and numerical study of a mathematical model describing the competition of CAR-T, leukaemias tumor and B cells. The model is formulated and its basic properties are investigated. A study of the existence of equilibrium points and its stability is done. Of great importance is the relapse of tumor cells and we study this fact in the article. Finally, we make a sensibility analysis in order to gain insights on the most relevant parameters of the model. We discuss these results in the light of the available evidence.