SERTAD1 and plasma cell myeloma: Subsequent experimental validation corroborated that downregulating the expression of STING or IRF7 in myeloma cells markedly attenuates the induction of SEI1 by melphalan or bortezomib (Figure 4J,K), and downregulation of SEI1 reduced the induction of PD‐L1 by melphalan or bortezomib (Figure 4L,M).