PDCD1 and colorectal neoplasm: The growth inhibition due to ciprofloxacin and anti-PD1 alone was augmented by the combination of ciprofloxacin and anti-PD1 in the colorectal tumor model (p = 0.033 for anti-PD1 and p = 0.038 for ciprofloxacin, respectively) (Figure 5a).