CXCL9 and neoplasm: ICOSL expression on activated APCs plays a critical costimulatory role in T‐cell activation.[85] More importantly, ICOSL has been recognized as having potential functional importance in DC‐mediated (cross) priming of tumor‐specific T‐cell responses in vivo.[86] Our findings indicate that inhibiting the ICOSL signaling pathway results in the inability of Mig cDC1s to effectively induce the differentiation of TTSM and TPEX cells after combined treatment, concurrently leading to the loss of tumor inhibition.