PDCD1 and colorectal carcinoma: Furthermore, RCE plus Oxa significantly increased hPD-1 CD3+CD8+ T cell-mediated MC38 CRC cell killing from 50 μg/mL and 100 μg/mL of RCE combined with 2.5 μg/mL of Oxa treatment groups to a greater extent than RCE or Oxa alone for 24 h, 48 h, and 72 h.