“…In 1970, Keller and Segel proposed a celebrated mathematical model to describe the chemotaxis phenomenon [20,21]. Since these interesting works of Keller and Segel, many variants of chemotaxis models have been proposed and their dynamics have been studied intensively mainly on homogeneous environments [1,3,4,5,6,7,10,12,13,17,18,19,22,30,36,40] and [24,25,26,27,28,29,34,35,36,37,38,39]. In particular, we refer to the survey papers [2,8,9].…”