TIGIT and lung cancer: Targeting immune checkpoint receptors (ICRs) such as lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin-domain-containing-3 (TIM-3), and T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) represent a promising immunotherapy for lung cancer treatment.