CT45A1 and colorectal carcinoma: Although a low frequency of CIC structures (1–2%) was observed in MSI‐H CRC cells (Fig. S5B), the outer NK cell‐resistant, CT45A1‐expressing cancer cells in established homotypic CIC structures prevented the targeting of antibodies to inner cancer cells (Fig. 3K), indicating the formation of homotypic CIC structures may reduce the therapeutic efficacy of antibody‐conjugated oligonucleotides (ACOs), antibody‐conjugated drugs (ACDs), or ADCC.