Abstract: Sarcomatoid renal cell carcinoma (sRCC) is an uncommon kind of renal cell carcinoma with sarcomatoid differentiation, which confers aggressiveness and a dismal prognosis. The epithelial–to-mesenchymal transition (EMT) is related to the sarcomatoid change of renal cell carcinoma. Driver mutations are noted in TP53, NF2, BAP1, and ARID1A. Abnormal epigenetic regulations may also trigger sarcomatoid transformation. Treatment includes surgery, targeted therapy, and immunotherapy. With a higher tumor mutational burden and a high expression of PD-1/PD-L1, PD-1 or PD-L1, immune checkpoint inhibitors (ICIs)-based regimens play an important role in the treatment of sRCC. In this review, we summarize the pathogenesis of sRCC and the mechanism of PD-1 or PD-L1 ICIs-based immunotherapy.