SPP1 and neoplasm: Besides the increased proportion of tumor-infiltrating γδ T cells in the PW group, higher expression of Cd40lg was observed in γδ T cells than other cell types, particularly in mice with intact gut microbiota or/and ICI treatment, while the expression of its receptor (i.e., Cd40) was specifically elevated in APCs, such as Cd74+ macrophages, which are upregulated through macrophage reprogramming from Spp1+ macrophage in the PW group.