PDCD1 and neoplasm: Despite the majority of inter-immune communications with myeloid cells occurring in both sides (including pro-tumor pairs like SPP1-CD44, LAMP1-FAM3C, and MERTK-GAS6), CD20+ B cells specific to the right side are a favorable prognostic marker and have been demonstrated to be essential for the efficacy of anti-PD-1 therapy in murine models and patient-derived organoids (Ji et al., 2024).