Abstract Background ADCs combined with immunotherapy represent a promising anti-cancer approach. However, such combinations often result in increased toxicity. Subcutaneous (SC) delivery offers a safer alternative, with comparable efficacy to intravenous delivery, as demonstrated by treatments like amivantamab. JSKN033 is a FDC for SC injection, utilizing innovative technology, comprising JSKN003, a biparatopic HER2-directed ADC, and KN035, a NMPA-approved PD-L1 inhibitor.