However, the multifaceted roles of these two proteins in different cancer studies, and the fact that inhibition of STAT3 or STAT1 may indirectly affect many other processes, suggest that STAT3 and STAT1 inhibitors may give rise to unpredicted and undesired effects; additional limitations may also exist when STAT3 and STAT1 are targeted in clinical protocols combining ICBs [20,36,37]. This evidence concerns the gene STAT1 and cancer.