library_construction_protocol: Subcutaneous B16 tumours were implanted on the back mice. On day 12, 100 ug of tissue was harvested from each tumour and stored in RNAlater at -80C. RNA was extracted using Tiissue Lyser II Homogenizer (Qiagen) and RNEasy Mini Kit (Qiagen) according to manufacturer's instructions. Complete V(D)J variable regions of TCR transcripts were captured using the SMARTer Mouse TCR a/b Profilinf Kit (Takara) according to manufacturer's instructions.