With the same initial settings and obstructing rate of CTLA-4, u=0.76, if the dosage of oncolytic virus is s=9×106 on day 8 as the tumor size reaches to 4×107 and the treatment lasts for 5 days, the susceptible tumor size is 2.2660×107 on day 18 post-implantation. Here, CTLA4 is linked to neoplasm.