The present invention relates to the field of medicine which needs to provide antibodies that bind human PD-1 with higher affinity than known PD-1 antibodies. The present invention thus provides antibodies that bind human programmed cell death 1 (PD-1) and are useful for treating cancer alone and in combination with chemotherapy and other cancer therapeutics. The antibodies provided comprises the light chain CDRs RASQGISSWLA, SAASSLQS and QQANHLPFT； and heavy chain CDRs wherein HCDR1 is KASGGTFSSYAIS or KASGGTLSSYAIS, HCDR2 is LIIPMFGTAGYAQKFQG or LIIPMFDTAGYAQKFQG or LIIPMFGAAGYAQRFQG, and HCDR3 is ARAEYSSTGTFDY or ARAEHSSTGTFDY.
