“…So far, various schemes have been introduced to control nonlinear systems [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ]. As well, for HIV–immune systems, as nonlinear systems, there are a wide variety of controllers in the literature, including a fuzzy discrete event system approach [ 59 , 60 ], feedback control [ 61 , 62 ], sliding mode control [ 14 ], and optimal control [ 63 , 64 , 65 , 66 , 67 ].…”