PDCD1 and lung cancer: The most frequently occurring keywords included “immunotherapy,” “lung cancer,” “chemotherapy,” “PD-L1,” “targeted therapy,” “non-small cell lung cancer,” “nivolumab,” “pembrolizumab,” “PD-1,” and “immune checkpoint inhibitors.” This analysis identified the top 10 most cited keywords in the literature on immunotherapy for lung cancer (Figure 4C), visually demonstrating the periods with higher publication volumes for different hotspot keywords.