PDCD1 and cancer: Furthermore, we found that LCK was significantly correlated with TIGIT (Figure S19E, total rho=0.82), CTLA4 (Figure S19F, total rho=0.77), and PD-1 (Figure S19G, total rho=0.81) in most cancer types, indicating the important role of TIGIT, CTLA4, and PD-1 in the TIL-T cells across cancer types.