In addition, the combination of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and EGFR-TKI for previously treated EGFR-mutant NSCLC was investigated, but most studies were discontinued in the early phase because of low efficacy and toxicity (e.g., tremelimumab and gefitinib [47], ipilimumab and EGFR-TKI or ALK-TKI [44], erlotinib and atezolizumab [48], and pembrolizumab plus gefitinib or erlotinib [49]). Here, EGFR is linked to non-small cell lung carcinoma.