There are monoclonal antibodies targeting the PD-1/PD-L1 pathway (nivolumab, pembrolizumab, avelumab, atezolizumab, and durvalumab) that provide antitumor immunity by removing this impediment and may be a potential therapeutic method for inhibiting mast cell-associated tumor growth (Varricchi et al., 2017; Lv et al., 2019; Zhao et al., 2020). Here, PDCD1 is linked to neoplasm.